We are nationals of India, with valid Canadian PR cards. As we have a 22-hour layover in London, with an onward flight to Canada, can we get a transit visa (48 hours) after landing at LHR (Terminal 4)?
According to gov.uk you are eligible for a transit visa if:
- you’ll be in transit to another country, with enough funds and the intention to travel on
- you can enter that country
- the only purpose of your visit to the UK is transit
- Leave the UK within 48h
Based on the information you have given you meet these requirements, with your Canadian PR cards you can enter Canada, you are within the 48h timeframe and you are only transitting.
EDIT: After reading your question again based on Henning Makholms comment on you wanting to get the VISA after landing, that is not possible, at all.