Tourist Visa overstay due to cancelled flight scenario

Hi

My mom's tourist visa expires on 10th october and she got last flight of the day on qatar airways on the same day. If her flight cancels that day and they take her next day would she be counted as overstayer and cause problem for future visa application?

Thank you

How long did she apply to stay in the UK in the visa application form?

i think thats irrelevant, but she applied for 6 months visa period starting April 10 to October 10th.

Provided she has gone past the exit checks on the day, I think she will be fine and not be an overstayer.

However, be aware that the Home Office has started looking closely at visit visa applications of people who stay in the UK for the full six months of their visit visa. The idea of a visit visa is that they visit for a short period at any time within the six months. They should not be residing in the UK in the guise of a visit visa.

"4.2 (a) (c) (e) of Appendix V, Immigration Rules of Visitors" states:

The applicant must satisfy the decision maker that they are a genuine visitor. This means that the applicant:
(a) will leave the UK at the end of their visit; and
(b) will not live in the UK for extended periods through frequent or successive visits, or make the UK their main home; and
(c) is genuinely seeking entry for a purpose that is permitted by the visitor routes (these are listed in Appendices 3, 4 and 5); and
(d) will not undertake any prohibited activities set out in V 4.5 – V 4.10; and
(e) must have sufficient funds to cover all reasonable costs in relation to their visit without working or accessing public funds. This includes the cost of the return or onward journey, any costs relating to dependants, and the cost of planned activities such as private medical treatment.

Even after getting the visit visa, if the Immigration Officer at the airport comes to the conclusion that the visitor is residing in the UK in the guise of a visit visa, they can cancel the visit visa on the spot and have them sent back to their country of origin. As that would be on their record, that would also make it very difficult if not impossible for them to get a visit visa in the future.

So factor all of that in before booking a return ticket.

Thank you very much for detailed response. on her previous visit in 2014 she stayed for 30days but this time she will be staying for about 150 days(she came 12th May and going back 10th oct) im sure she should be fine.

The returned ticked was booked already when she came here, im just thinking if in case of cancellation if she will become overstayer then i would rather change ticket to couple of days earlier which will cost me extra ££ too.