Visa National Overnight at Heathrow?
I can't find a clear statement anywhere, so I'm asking here.
I'm trying to find out if a visa national (more trusted tier) can change planes at Heathrow if the scheduled time on the ground straddles midnight. The plan is to stay airside. The scheduled time on the ground is definitely less than 24 hours, but I'm not sure what the requirement to arrive and leave on the 'same day' means. If the times were swapped round, so arrival and departure were on the same date, she should have no problem, but getting a 'visitor in transit' visa would be a major hassle.
Border Force officers asked off duty have given different answers!
The various exemptions based on other visas don't hold; all she has is a Shengen tourist visa.
If the visa national were Indian, she would need at least a Direct Airside Transit visa (DATv), but that would not be good enough for a delay straddling midnight. The visa national of concern is exempt from needing a DATv; she needs either a visitor in transit visa for the UK or needs no visa for the UK.