The document your bid answers
What Is an Invitation to Tender (ITT)?
An invitation to tender (ITT) is the pack a public buyer issues inviting suppliers to submit a formal, priced bid for a defined contract. It sets out the specification, the conditions of participation, the award criteria and weightings, the contract terms and the submission rules. Reading it in full, criteria first, is the foundation of every winning bid.
Published by BidSquirrel · checked against legislation.gov.uk and gov.uk · last reviewed July 2026
Every formal public-sector bid answers a document, and that document is usually called an invitation to tender - the ITT. It is the buyer's complete brief: what they want, how they will judge the responses, what you must include, and how and when to submit. Get the ITT wrong - skim it, miss a mandatory question, misread the weightings - and no amount of good writing recovers the marks.
This guide explains what an ITT actually is, what sits inside the pack, how it differs from the earlier stages of a procurement, and how a small business should read one before writing a single answer. It is the orientation guide the rest of the responding-to-a-tender cluster builds on.
What an ITT is - and what it is not
An invitation to tender is the formal request a contracting authority issues to invite priced, structured bids for a specific contract. It marks the point where a procurement stops being about market interest and starts being about your actual offer: your method, your evidence, your price, submitted against a published rubric. "Invitation to tender" is a practitioner term rather than a phrase defined in the Procurement Act 2023 - under the Act you will also see notices called tender notices and associated tender documents - but the function is universal: it is the pack your bid responds to.
It is not a pre-market exercise and not, on its own, a guarantee you are eligible. Earlier stages - pipeline notices, preliminary market engagement, and on some procedures a selection or shortlisting stage - come first. On a single-stage open procedure the ITT and the selection questions arrive together; on a multi-stage procedure you clear the selection stage before you are invited to tender at all. Knowing which you are in tells you what the ITT is actually asking of you.
What is inside the pack
ITTs vary in length from a few pages for a small contract to hundreds for a complex one, but the anatomy is consistent. Read for these components before you write anything:
- The specification or statement of requirements - what the buyer actually wants delivered, and the outcomes it is buying
- Conditions of participation - the pass/fail gates about your firm (financial standing, insurance, certifications, relevant experience) that you either meet or do not
- Award criteria and weightings - how the bid will be scored, the quality/price split, and the marks attached to each question; this is the map to where the effort should go
- The response documents - the actual questions to answer, with word or page limits, plus the pricing schedule
- Contract terms and conditions - the terms you are agreeing to if you win, including KPIs, payment terms and any social-value commitments
- Submission instructions and the deadline - the portal, the format, and the hard cut-off after which the system will not accept your bid
How to read an ITT before you write a word
The winning habit is counter-intuitive: read the ITT backwards. Start with the award criteria and weightings, because they tell you where the marks are and therefore where your time should go - a strong answer to a lightly weighted question is wasted effort, and a weak answer to a heavily weighted one is fatal. Our guide on how tenders are scored covers the mechanics of the weightings in detail.
Then check the conditions of participation before you invest a day in writing: if you cannot clear a mandatory gate - a certification you do not hold, an insurance level you cannot reach - the bid is a no-bid, and it is far cheaper to learn that on day one than day ten. Our bid or no-bid guide covers that decision. Finally, note the submission rules and deadline, and use the clarification facility for anything ambiguous rather than guessing - answers are usually circulated to all bidders, and a good question signals competence. Once you have read it this way, our guide on how to respond to an ITT walks through building the response itself.
Take this to a live tender
Reading is the groundwork. When you are ready to act on it, BidSquirrel scores live tenders from major GB sources against your business, tells you which are worth bidding, and drafts the response with you - free to start, no card.
Frequently asked questions
What is the difference between an ITT and an RFP or RFQ?
In UK public procurement "invitation to tender" is the common term for the formal bid pack; "request for proposal" (RFP) and "request for quotation" (RFQ) are broader commercial terms you will also meet, an RFQ usually implying a simpler, more price-led request. The function is the same - a defined brief you submit a structured, priced response to.
Is an ITT a legal term under the Procurement Act 2023?
Not exactly. "Invitation to tender" is a widely used practitioner term; the Act itself refers to tender notices and associated tender documents. Whatever it is labelled, it is the pack that sets out the requirement, the award criteria and weightings, the conditions of participation and the submission rules your bid must answer.
Do I have to answer every part of an ITT?
You must satisfy every mandatory requirement and answer every scored question you can - unanswered scored questions simply score zero, and a missed pass/fail condition of participation can disqualify the whole bid. Read the whole pack first so nothing mandatory is missed, and use the clarification facility for anything unclear.
Read every ITT with the scoring in view
BidSquirrel reads the tender documents with you - surfacing the award criteria, weightings and conditions of participation - so you know where the marks are before you write. Then it drafts each answer from your own evidence against what the criterion rewards. The final words stay yours.