What GOV.UK says about bookings
The Home Office's Guide to supporting documents: visiting the UK includes a list of documents that are "less useful as evidence". That list includes "flight bookings (unless transiting)" and "hotel bookings".
The same guide warns that submitting any document does not guarantee your application or entry at the border will be successful, and says: "You should bear this in mind when making any bookings."
In plain terms: you are not required to show a flight booking, and you shouldn't buy an expensive non-refundable ticket before a decision.
So when does a reservation still help?
- You are transiting the UK. GOV.UK specifically excludes transit from the "less useful" note — showing your onward flight is relevant.
- Your travel agent, sponsor or employer asks for one to plan dates, or to issue an invitation letter with specific dates.
- You want a written plan for yourself so the dates on your form, leave approval and invitation letter all agree.
If none of these apply to you, you may not need to buy anything from us for a UK application. We'd rather tell you that than sell you a document you don't need.
What to focus on instead
The guidance puts more weight on evidence about you: your circumstances at home, your finances, and the purpose of your visit. Read the full GOV.UK guide linked below and gather those documents first.
If you're visiting more than one country
Travellers combining a UK visit with a Schengen trip often need a reservation for the Schengen application anyway. See our Schengen guide for what the European Commission lists.