Transit Visa Connecting flight to India

[Avisekm]

Hello,
I am travelling from Toronto to India with stopover of 2 hours at Heathrow and 1 hour at Frankfurt,
Please let me know if I need a transit visa even if I am not leaving the airport.
my itenary is Toronto-Heathrow-Frankfurt-Bangalore.
I have a valid work visa and work permit for Canada and travelling to India for 1 week.
Would appreciate if someone can revert back asap.

Thanks a lot in advance.