Most GP partnerships run a mutual assessment period: a trial stretch, often around several months to a year but practice-specific, during which the incoming GP and the existing partners decide whether to offer and accept parity or permanency. This page explains what the mutual assessment period is, and then gives you the substance: the financial due diligence an incoming GP should do during it. Read the accounts, understand the premises position and last-man-standing risk, check the NHS contract and the list, read the partnership deed, understand drawings versus profit, and surface any outstanding liabilities.

It is the look-before-you-leap page for joining a partnership, framed around the trial period that gives you the window to do it. For the broad consequences of becoming a partner (the status change, drawings versus profit, National Insurance, pension and premises risk), see our guide to the financial implications of becoming a GP partner. This page is general information, not legal or personal advice.

What the Mutual Assessment Period Is

A mutual assessment period is a trial period before a partner is offered parity or made permanent, during which both sides assess whether the fit works clinically, collegiately and financially. Its length is set by the practice and the deed and is commonly several months to around a year, but it is practice-specific, so we do not lock a standard length; any figure quoted as typical is illustrative only.

Its purpose runs both ways. The existing partners are deciding whether to commit to you, and you are deciding whether to commit to a business with real liabilities and a long-term premises commitment. It is the natural window in which to do your financial due diligence. It is distinct from parity, the route to a full, equal share, which we cover in our guide to buying into a GP partnership and how parity works. During a mutual assessment period a new GP may be salaried or on a reduced share, with the deed and the offer letter setting the basis.

It is also worth distinguishing the mutual assessment period from a straightforward salaried trial. A salaried GP who later becomes a partner has simply been an employee until the moment they join; a mutual assessment period is explicitly framed as a step on the road to partnership, with both sides treating it as the run-up to a buy-in and parity rather than an open-ended job. The practical difference for you is mindset: during a mutual assessment period you should be actively gathering information and forming a view on whether to commit, not waiting passively to be offered something. The clock is running on a decision, and the documents you need to make it well take time to obtain and digest.

Why Due Diligence Matters as Much for the Joiner as the Practice

There is an asymmetry worth naming. The practice is assessing you, but you are also buying into a business with its own liabilities, and on entry you take a share of the partnership's tangible assets, any owned premises and the capital accounts. The cost of poor diligence is not a single bad year; it is potentially years of exposure to a premises liability, a borrowing or a contract you did not properly understand.

The mutual assessment period exists precisely so that both sides can find out before committing. For what the consequences of partnership look like once you are in, our financial implications guide sets them out; this page is about the checks you do before you reach that point.

Check 1: the Accounts

Which Accounts to Obtain

Ask for at least the last two to three years of partnership accounts, and, where the premises are held separately, the property-partnership accounts as well. A GP partnership files a single partnership return (the SA800), and each partner's share flows to the partnership pages (the SA104) of their own return, taxed as trading income with Class 4 National Insurance. To read the accounts you obtain line by line, our guide to reading GP partnership accounts is the companion to this section.

What to Look For

Look at the profit trend over the years you obtain: is it stable, rising or falling, and why. Look at the profit per partner or per session, the split between NHS and private income, and any heavy reliance on a single income stream such as a large enhanced service or a particular PCN role. Read the expenses profile too, the staff costs, locum reliance and finance costs. Practice income comes through the Global Sum (weighted by the Carr-Hill formula), QOF, enhanced services and PCN or Network Contract DES funding, with no single national per-patient value, so judge the figures on stability and trend rather than against a fixed benchmark.

Pay particular attention to anything that explains a swing in the numbers. A spike in profit driven by a one-off enhanced service that has since ended, or by a vacancy that suppressed staff costs for a year, tells you something very different from steady underlying growth. Equally, a year of depressed profit caused by a major refurbishment or a run of locum cover may be temporary rather than a sign of decline. The point of reading two or three years together is to separate the underlying trajectory from the noise, so that you understand what your share is likely to be worth once you reach parity rather than what it happened to be in any single year. Where the accounts raise questions you cannot answer from the document, those questions make an excellent agenda for a conversation with the practice and with your own accountant.

Drawings Versus Profit and the Current Accounts

Because a GP partner is taxed on profit share, not drawings, check that partners' drawings are not running ahead of profit, and look at the current-account balances: are partners overdrawn, or is there undrawn profit funding the practice? Overdrawn current accounts can be a warning sign about how drawings are set. Our guide to drawings versus profit and tax reserving explains why the gap matters and how a sound practice manages it.

Check 2: the Premises Position and Last-Man-Standing Risk

Are the Premises Owned, Leased or Reimbursed

Establish how the premises are held: owner-occupied through a separate property partnership or LLP, leased from a third party, or NHS or PropCo owned. Establish how income support flows, through notional rent for owner-occupiers (a current-market-rent basis) or the legacy cost rent scheme. These amounts are District Valuer or surveyor assessed and property-specific, so there is no standard figure to expect.

What Documents to Read

The core premises documents are the lease, the property-partnership deed, the title, any mortgage or borrowing secured on the premises, the last notional-rent review, and any rent-review or break clauses. These are not optional extras in the diligence; they are central to understanding what you would be taking on if you buy a premises share or sign the lease.

Last-Man-Standing Exposure

If you take a premises share or sign the lease, ask what happens when partners leave and are not replaced. The last-man-standing risk, a single remaining partner left holding the whole premises liability and lease, is a real planning point for any incoming partner. We cover it in depth in our guide to last-man-standing premises risk, and the wider own-versus-rent picture in our guide to owning versus renting surgery premises.

The way to test your exposure during the mutual assessment period is to ask concrete questions rather than accept reassurance. Who is currently on the title or the lease? What is the age profile of the partners, and how many are likely to retire within the term of the lease or the life of the mortgage? If a partner leaves and no replacement is found, who picks up their share of the premises commitment, and is there anything in the deed or the lease that protects the remaining partners? A practice with a younger partner profile and a flexible lease sits very differently from one where several partners are near retirement on a long full-repairing lease. The premises position is often the single largest long-term financial commitment attaching to partnership, so it deserves the most careful diligence of all, with your solicitor reading the lease and property documents alongside you.

Check 3: the Contract and the List

The income side deserves its own diligence. Establish which NHS contract the practice holds (GMS, PMS or APMS) and whether it is stable, the registered list size and its trend, and the patient demographics as they affect weighted funding under the Carr-Hill formula. Check the dependence on QOF, enhanced services and PCN or Network Contract DES income, and any dispensing income. There is no single national per-patient value, and the figures uplift annually, so treat any number you are quoted as date-tagged rather than fixed.

List size matters more than it first appears, because so much core funding flows from the weighted list. A list that is shrinking, or that depends heavily on a population the funding formula does not weight generously, can put quiet pressure on income that a single year's accounts will not reveal. Look at the direction of the list over the years you have, and ask what is driving it: a closing list, a new housing development feeding patients in, or competition from a neighbouring practice all point to different futures. The contract type matters too, because a stable GMS contract sits on a different footing from a time-limited APMS contract that may be re-tendered. None of this is to say a smaller or differently funded practice is a poor choice, only that you should understand the income engine before you commit a share of your career to it.

To confirm the income shown in the accounts is actually being paid correctly, our guide to reconciling the GP practice income statement walks through the checks, and our wider GP financial planning guide puts the income picture in its personal context.

Check 4: the Partnership Deed

The partnership deed is the single most important document, and you should read it for the following.

  • Profit-sharing method and the parity timetable (the buy-in and parity mechanics are covered in our guide to buying into a GP partnership).
  • The buy-in and buy-out terms, including how the figure is set and how capital is returned on exit.
  • Drawings and how the year-end true-up works.
  • Capital accounts and how capital is dealt with on a partner leaving.
  • Decision-making and majority provisions.
  • Restrictive covenants.
  • Maternity, paternity and sickness provisions.
  • Expulsion and dispute clauses.
  • Premises provisions, including last-man-standing.

The deed should be read by a specialist solicitor and a medical accountant together: the accountant on the numbers and the tax, the solicitor on the legal terms. This page does not give legal advice on the deed; it tells you what to have reviewed and by whom.

It is also worth checking that a current, signed deed actually exists. Some partnerships operate for years on an out-of-date deed, or worse on no written deed at all, in which case the default partnership law position can apply in ways none of the partners intended. A practice that cannot produce a current deed during your mutual assessment period is telling you something about how its affairs are run, and the absence of clear written terms on profit sharing, parity, capital and the premises is a risk in itself. If the deed needs updating to reflect your joining, that work should be done and agreed before you commit, not left as a loose end to sort out after parity.

Check 5: Drawings, Working Capital and Cash Flow

As a self-employed partner your cash flow changes. You draw against anticipated profit, you make payments on account, and your share is trued up at year-end against the finalised accounts. As part of your diligence, understand the practice's working-capital position and whether you will be asked to fund a share of it, and budget for tax reserving from day one rather than after your first surprise bill. Our drawings versus profit and reserving guide sets out the discipline, and the financial implications guide covers the cash-flow shift in more detail.

The cash-flow change is one of the most under-appreciated parts of the move, particularly for a GP coming straight from a salaried post where tax was deducted at source and the monthly figure was predictable. As a partner you receive drawings, not a salary, and you are responsible for setting aside tax yourself. In the first year especially, payments on account can land before you have a full year of partnership income behind you, so the timing can feel uncomfortable. Using the mutual assessment period to understand how the practice sets drawings, how often they are reviewed, and what the year-end true-up process looks like means you can plan your personal finances around the reality rather than being surprised by it.

Check 6: Outstanding Liabilities and Contingent Risks

Surface the liabilities an incoming partner could inherit a share of:

  • Practice borrowings and any personal guarantees.
  • Premises mortgage and lease commitments.
  • Dilapidations exposure on a leased surgery.
  • Employment liabilities, including redundancy or TUPE-type exposure on a merger.
  • Any pension or tax issues sitting in the accounts.
  • Outstanding NHS clawbacks or income disputes.
  • Any CQC or regulatory history, a standard transaction due-diligence item.

None of these is necessarily a deal-breaker, but each is something you want to know about before you commit rather than after. The reason liabilities matter so much for an incoming partner is that partnership brings shared responsibility: you can become exposed to a share of obligations the practice took on before you arrived, depending on the terms of the deed and any guarantees you are asked to give. A borrowing taken out years ago to fund a premises improvement, or a lease with onerous repair obligations, becomes part of your world the moment you join. Asking for a clear schedule of the practice's borrowings, guarantees, lease commitments and any disputes is not being difficult; it is exactly the diligence the mutual assessment period exists to allow. For the wider risk picture once you are in, see the financial implications guide.

Check 7: Pension and Personal Tax

One short check, signposted rather than taught here. Confirm how partnership profit will affect your NHS pension (as a partner you pension your NHS-derived profit as a Type 1 medical practitioner), and whether higher profits risk the annual-allowance taper. Confirm too that you will move to Self Assessment with payments on account. This is covered in depth in our guides to GP pension contributions and tax relief and GP financial planning, and in the financial implications guide.

The reason this belongs in your diligence, even as a signpost, is that a rising profit share is mostly good news but can carry a tax consequence that is easy to miss. As your share grows towards parity, your pensionable profit grows with it, and a partner whose income crosses the relevant thresholds can find the annual allowance tapering down, with a charge to settle if their pension growth exceeds it. None of this is a reason to turn down a profitable partnership, but it is a reason to model your pension position alongside your income rather than discovering an annual allowance charge after the fact. Flagging it now, while you still have the choice of whether to commit, means you can plan for it rather than react to it.

A Due Diligence Checklist for the Mutual Assessment Period

Drawing the above together, the documents to obtain and the questions to ask during the mutual assessment period are:

  • Two to three years of partnership accounts (and any property-partnership accounts), read with our accounts reading guide.
  • The partnership deed, reviewed by a specialist solicitor and a medical accountant together.
  • The lease and property documents, with the last-man-standing position established.
  • The NHS contract and list data, and recent income statements reconciled with our income reconciliation guide.
  • Details of borrowings, guarantees and dilapidations.
  • The buy-in and parity terms, covered in our buy-in and parity guide.
  • How you will finance any buy-in, covered in our financing a buy-in guide.
  • The drawings and capital-account position across the partners.

How We Help GPs During a Mutual Assessment Period

We work with GPs across the UK through the mutual assessment period, turning a daunting set of documents into a clear picture. That means reading two to three years of accounts for the profit trend and the current-account position, sense-checking the income against the contract and the list, flagging the premises and last-man-standing exposure for you and your solicitor, and modelling what your drawings, tax reserving and pension would look like once you reach parity. We work alongside a specialist solicitor on the deed rather than in place of one.

The aim is that, by the end of the trial period, you are deciding with full information rather than on trust. You can read more about how we support GPs on the for GPs page, or get in touch to talk through a specific opportunity. The wider GP tax and accounts category collects our related guides.