I am an Indian citizen travelling from India to Italy on a student visa via the UK. My flight stops at Heathrow for 2.5 hours. Will I be required to have a transit visa?
Indian citizens generally do need a visa for airside transit at Heathrow but you are probably exempt from this requirement based on your Italian visa. Specifically, you are exempt if you:
have a valid uniform format category D visa for entry to a state in the European Economic Area (EEA)
An Italian student visa valid for more than three months would be a category D visa (whereas a short-stay Schengen visa would not). If I am not mistaken, it should look approximately like this: