Supplier, bidder and contractor
Supplier, bidder, tenderer, contractor: the successive roles a company holds in a public procurement. Definitions, eligibility conditions and duties in the UK and Ireland.
Updated on September 5, 2026
Supplier is the word the Procurement Act 2023 uses for any person, company or other body that provides, or could provide, goods, services or works to a public buyer. A bidder or tenderer is a supplier that has submitted a tender; the successful one becomes the contractor, sometimes called the incumbent once the contract is running.
How it works
These words describe the successive stages of a competition. Any company, sole trader, partnership, charity, mutual or public body can be a supplier. No particular legal form is required, and a consortium can bid without setting up a joint company, although buyers often ask for a lead member and joint and several liability.
A supplier must show that no exclusion ground applies to it — convictions for certain offences, unpaid tax, insolvency, serious professional misconduct, poor performance on an earlier public contract — and that it meets the conditions of participation the buyer has set: legal and financial capacity and technical ability, both of which must be proportionate to the contract. Since the Act came into force on 24 February 2025 (verified 2026-09-05), suppliers in England, Wales and Northern Ireland register once on the Central Digital Platform within Find a Tender, enter their core company information there and quote the resulting supplier identifier in each tender. Irish suppliers still complete the European Single Procurement Document on eTenders, as do bidders in Scotland.
In an open procedure, selection information and the tender are submitted together. In a two-stage competitive flexible procedure, suppliers are shortlisted first and only those invited go on to tender. The contractor remains responsible for the whole contract, including the work of its sub-contractors.
What it means for a bidder
A micro business or an SME is a supplier on exactly the same footing as a large group, and buyers must have regard to the barriers SMEs face. Requirements have to be proportionate: a minimum turnover test, for instance, should reflect the size of the contract rather than the size of the buyer.
Keep a current bid library: tax and insurance evidence, accounts, insurances at the levels buyers ask for, references, staff and equipment lists, health and safety and quality certification. If your own capacity falls short you may rely on another organisation, a sub-contractor or a consortium partner, provided you can show that its resources will genuinely be available to you.
A young company with no public sector track record can still bid, evidencing capability through private sector work and the qualifications of its people.
Example
A five-person software company answers a selection stage run by a fictional English university for a student portal rebuild, estimated at £180,000. As a supplier it evidences capability with the CVs of its developers and two private sector references. Shortlisted, it becomes a bidder by submitting a tender. Successful, it signs the contract and becomes the contractor.
Frequently asked questions
Can a company in administration bid?
It may be excluded on insolvency grounds, but buyers must consider the circumstances and any evidence that the business can perform the contract for its full term.
Is a sole trader a supplier?
Yes. Anyone carrying on an economic activity can bid, provided the eligibility conditions on tax, insurance and capability are met.
What is the difference between a bidder and a contractor?
A bidder has submitted a tender; the contractor has been awarded and has signed. In an open procedure a company is both in turn within a single process.