Requirements for bid bonds in the UK are not as common in domestic construction as they are in international markets. However, they do arise in certain public sector tenders and in some infrastructure and major commercial procurements. They may also appear in procurements run by housing associations where the organisation and contract fall within the scope of the Procurement Act 2023. When they do appear, both developers and contractors need clarity on what they are, how bid bonds work and what the practical implications are.
Understanding how bid bonds work is essential where a tender bond requirement is included in procurement documentation. For bidders, it can form part of the submission requirements. For employers, it is a form of early-stage financial security designed to mitigate withdrawal risk during the tender process.
What Is a Bid Bond in Construction?
A bid bond, also referred to as a tender bond, is a guarantee provided by a surety on behalf of a bidder. A bid bond provides the employer with financial security if the successful bidder fails to enter into the contract or provide specified post-award security, subject to the bond wording and call conditions.
Depending on the bond wording, the employer might recover an agreed sum or proven loss, subject to the bond limit. Recoverable loss might include additional procurement costs or the increased cost of appointing another contractor.
In practical terms, a bid bond construction UK requirement seeks to discourage unsupported bids and provides limited financial protection if the successful bidder fails to proceed.
Find more information on arranging bid bonds on our dedicated page.
Are Bid Bonds Common in the UK?
Bid bonds are less standard in domestic UK procurement than in international projects. In many private sector developments, particularly smaller schemes, they are rarely used.
They might be encountered in:
- Certain public-sector procurements
- Infrastructure projects
- Major commercial developments
- Some housing-related procurements where withdrawal risk is considered material
In these contexts, the employer may wish to mitigate the risk of a preferred bidder withdrawing after award. Their use is not universal and will depend on the specific procurement strategy adopted.
How Bid Bonds Work in Practice
Understanding how bid bonds work is easier when viewed as a step-by-step process during procurement.
Application before tender submission
Before submitting a bid, the contractor applies to a surety for a bid bond. The surety assesses financial strength, track record and overall capacity before agreeing to issue the bond.
Submission with the tender
The bid bond is included with the tender documents. It provides the employer with financial backing if the bidder fails to proceed in accordance with the procurement requirements.
If the bidder is unsuccessful
If the bidder is unsuccessful, the bond will normally expire or be released in accordance with its terms. The bidder should confirm whether formal cancellation or return of the original instrument is required.
Bidders should monitor the bond expiry date. Where the tender validity period is extended, the employer might also require an extension to the bond. Failure to secure an extension could affect the bid.
If the bidder wins but fails to proceed
If the winning bidder does not sign the contract or fails to provide the required performance bond and other securities, the employer may call on the bid bond, subject to its wording.
If the surety makes a valid payment, it will normally seek recovery from the contractor and any other indemnifying parties under the counter-indemnity.
The risk period for a bid bond is limited to the tender and award stage. Because this period is relatively short, the premium might be lower than for a performance bond, although pricing depends on multiple factors.
What Happens If the Winning Bidder Cannot Enter the Contract?
If the winning bidder cannot or does not enter into the contract, the employer may incur financial loss. This might include additional procurement costs or the increased contract price of appointing an alternative contractor.
A bid bond requirement procurement structure allows the employer to seek recovery up to the bond limit, subject to the bond wording. The amount recoverable will depend on whether the bond is on-demand, conditional, limited to proven loss or structured as an agreed damages instrument.
The surety does not automatically pay the employer’s calculated loss; payment is governed strictly by the bond terms.
How Much Does a Bid Bond Cost?
Because bid bonds normally cover a shorter period than performance bonds, the premium might be lower. Pricing depends on the bond value, wording, duration, contractor covenant and any wider surety facility in place.
The bond amount is set by the procurement documents. It might be expressed as a percentage of the tender value or as a fixed sum. Percentages used in some markets range from 5% to 10%, although UK requirements vary considerably.
The cost of the bond depends on:
- The bond value
- The duration of the tender period
- The bidder’s financial strength
- The complexity of the underlying project
- The bond wording and conditions
Employers might require the surety to satisfy an agreed financial-strength rating or credit standard. The legal effectiveness of the bond depends separately on its wording, execution and governing law.
Bid Bonds and the Procurement Act 2023
The Procurement Act 2023, which came into force on 24 February 2025, does not mandate bid bonds. Their use remains a commercial decision by the contracting authority.
Where a contracting authority requires a bid bond, the requirement, timing, form and consequences of non-compliance should be clearly disclosed in the procurement documents.
Where the requirement operates as a condition of participation, it must relate to the supplier’s legal or financial capacity or technical ability and must be proportionate to the nature, complexity and cost of the contract. Any bid bond requirement should be assessed carefully for proportionality. Where it is used as a condition of participation, the statutory proportionality requirements in section 22 apply.
For contractors bidding for public contracts, including procurements run by housing associations where the organisation and contract fall within the Procurement Act 2023, careful review of procurement documentation is fundamental. Bond requirements, form of wording and deadlines for submission should be understood before tender submission.
For broader context on surety products in procurement, see construction bonds explained.
The Difference Between a Bid Bond and a Performance Bond
A common source of confusion is the distinction between a bid bond and a performance bond.
A bid bond covers the tender period only. It protects the employer if the successful bidder fails to proceed to contract signature or provide required post-award security.
A performance bond covers the construction period. It protects the developer if the contractor fails to perform or complete the works in accordance with the contract.
On many projects, a bid bond is a precondition of tendering, while performance bonds are a condition of contract award. The two instruments operate sequentially, not interchangeably.
Are Bid Bonds Required Under the Procurement Act 2023?
The Procurement Act 2023 does not automatically require bid bonds. Where imposed, the requirement must be clearly stated in the procurement documents and structured lawfully.
Housing associations are not automatically subject to the Procurement Act. A housing association will fall within scope only where it meets the statutory definition of a contracting authority and the relevant procurement is covered by the Act.
Bid bonds can form part of a broader risk management strategy, but their use must be justified within the framework of the procurement procedure being followed.
Practical Considerations for Contractors
Contractors encountering a bid bond construction UK requirement should consider the following:
- Confirm the bond amount and required wording
- Establish whether it is a condition of participation or part of the tender submission
- Engage a surety early in the tender process
- Ensure internal approval processes are aligned with indemnity requirements
- Monitor expiry dates and potential extension requirements
Failure to provide the required bond in the correct form and by the stated deadline might result in rejection of the tender. The outcome will depend on the procurement documents, the status of the requirement and the authority’s lawful discretion.
LBB works with established surety markets and seeks terms that meet the employer’s stated credit, wording and procurement requirements.
Practical Considerations for Developers and Housing Associations
For employers, the decision to require bid bonds should reflect project scale, market conditions and withdrawal risk.
On larger projects, where bid preparation costs are substantial and programme certainty is critical, a bid bond can provide structured financial protection if the selected contractor does not proceed.
However, bond requirements should not be applied indiscriminately. Overly burdensome or disproportionate requirements may deter capable contractors from bidding, reducing competition and potentially affecting value for money.
Clear disclosure, lawful structuring and proportionality remain central considerations under the Procurement Act 2023.
Navigating Bid Bond Requirements
Bid bonds are less common in domestic UK projects than internationally, but they remain an established instrument within structured procurement environments. They provide employers with defined financial security during the tender phase and operate distinctly from performance bonds used during construction.
Understanding how bid bonds work, how payment depends on bond wording and how requirements interact with procurement rules is essential for both contractors and developers.
For guidance on arranging bid bonds or navigating bond requirements within public and commercial procurements, contact LBB for specialist advice.
