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I have an Indian passport and I'm currently working in Germany.
I am travelling from Dusseldorf--London Heathrow--Chennai. Transit time in London Heathrow is 1 hour 30 minutes, and connecting flight to Chennai departs on the same day and it is also from the same terminal.
I have a German residence permit(Aufenthaltstitel), and my German visa is type "D".
Could you please let me know if I require a transit visa in London?