A net contribution clause is a contractual mechanism that limits a professional's liability to a client to the share that would be judged just and equitable had a contribution claim been brought against every other party responsible for the same loss. In construction work, where a single defect commonly draws in an architect, engineer, supplier and contractor, the choice between net contribution and joint and several liability materially changes the professional's exposure under a professional indemnity policy.
Where two or more parties are liable in respect of the same damage, the Civil Liability (Contribution) Act 1978 gives any liable party a statutory right to recover contribution from any other liable party under section 1, with the amount recoverable assessed by the court as just and equitable under section 2 having regard to that party's responsibility for the damage. Absent a contractual carve-out, however, the client remains entitled to pursue any one defendant for the full loss. The client typically selects the defendant with the deepest pocket, or more accurately the defendant with the most responsive insurance, and leaves that defendant to chase the others through Part 20 contribution proceedings.
A net contribution clause reverses that risk allocation. The professional's liability to the client is capped at the share the court would have awarded had contribution been sought from every named co-contributor. Under the RIBA Standard Professional Services Contract 2020 and the professional appointments used alongside a JCT Design and Build 2016 Contract, net contribution wording is a standard drafting option. The commercial effect is that the client, rather than the professional, absorbs the recovery risk if a co-contributor is insolvent, uninsured or otherwise beyond reach.
In a business-to-business appointment the Unfair Contract Terms Act 1977 governs whether a net contribution clause is effective. Section 2 restricts exclusions of liability for negligence, section 3 restricts terms that seek to render a contractual performance substantially different from that reasonably expected, and section 11 sets the reasonableness test. In assessing reasonableness the court considers the relative bargaining power of the parties, whether the client received an inducement to accept the clause, the commercial context, and the availability of insurance to each side. A clause negotiated between a developer and a chartered practice, both professionally advised, is generally treated very differently from one imposed on an unrepresented small commercial client.
In a business-to-consumer engagement the position is stricter. Under section 65 of the Consumer Rights Act 2015 a trader cannot by a term of a consumer contract exclude or restrict liability for death or personal injury resulting from negligence, and the wider fairness test in Part 2 of the Act catches attempts to limit consumer remedies. A net contribution clause deployed against a consumer client (for example a homeowner engaging an architect on a domestic extension) is likely to be unenforceable, and prudent drafting reflects that.
For a professional with a net contribution clause in place, the maximum exposure to any single client claim is materially lower. The insurer's risk on that appointment is correspondingly reduced, and the clause is one of the factors underwriters take into account when rating a professional indemnity risk. Architects and engineers who consistently use net contribution wording — and who can evidence the practice through their engagement letters — often see this reflected in the terms offered at renewal.
The clause is not a substitute for evidence. To rely on it, the professional and insurer must identify the co-contributors and quantify their share of responsibility. That evidential burden is one reason net contribution disputes tend to settle rather than run to trial.
An architect signs a JCT Design and Build 2016 appointment on a mixed-use scheme, with a net contribution clause naming the structural engineer, cladding supplier and main contractor as co-contributors. Some years after practical completion a fire-safety defect emerges and the client brings a claim against the architect valued at £1.2 million. Investigation identifies responsibility as: structural engineer 25 per cent, cladding supplier 35 per cent, main contractor 10 per cent, architect 30 per cent.
Under the net contribution clause the architect's liability to the client is capped at 30 per cent of £1.2 million, or £360,000. The client must pursue the other 70 per cent from the remaining contributors directly. Had the appointment been silent on the point, the architect could have faced the full £1.2 million as a matter of joint and several liability and would have needed to bring Part 20 proceedings against the engineer, supplier and contractor to recover the balance. Net contribution is quicker and simpler for the professional; the trade-off is that recovery risk (in particular the risk that a co-contributor is insolvent) sits with the client.
See the Apex pillar guides on architects' professional indemnity insurance, engineers' professional indemnity insurance and design and build contractors' professional indemnity insurance, and the companion wiki entry on the Civil Liability (Contribution) Act 1978.
Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority. Firm reference number 724952. This entry is general information, not advice on any particular policy.