Upvote:6
It seems that you would probably be OK, although as ever, if you want to be "safe", then applying for a visitor in transit visa makes things much more straightforward.
You can find the full rules for Transit Wiwhout Visa (TWOV) on gov.uk (sections v7.6 - 7.10).
As we already know that you meet the requirements of v7.8(a), I'll quote V7.7 here so you can make sure it's all covered:
V 7.7 The applicant must:
- (a) have arrived by air and will be departing by air; and
- (b) be genuinely in transit to another country, meaning the purpose of their visit is to transit the UK and that the applicant is taking a reasonable transit route; and
- (c) will not access public funds or medical treatment, work or study in the UK; and
- (d) genuinely intend and be able to leave the UK before 23:59 hours on the day after the day when they arrived; and
- (e) have a confirmed booking on a flight departing the UK before 23:59 hours on the day after the day when they arrived; and
- (f) be assured entry to their country of destination and any other countries they are transiting through on their way there.
Note that all of those requirements must be met. You may have a "landing interview" where you are quizzed on your plans. If the border officer is not satisfied that you are a "genuine visitor" you may then be denied entry. Having an existing visa (transit should be fine I think) makes this more likley to go smoothly.