I applied for UK visitor visa and was granted one with a start date of April 15. I will be leaving US April 14, and arriving London April 15, will this visa be valid? Thanks
UK visas are valid for entry from the start date. The expiry date is the latest date by which you must leave. Your departure date doesn’t matter - you can enter on any day between the two beginning with the start date. One conceivable problem with departing the day before would be if your flight was scheduled to land in the UK shortly after 00:01 the following day, but arrived ahead of schedule prior to midnight on the departure date.