Does H1B approved petition but expired stamping needs UK Transitvisa from US to India

[prsh16]

Hi,


I have a question for UK transit visa .
Actually I have valid approved US H1B petition but expired visa stamping of oct 2014 in my passport as after coming to US I didn't go back since last year to India.

Now I am traveling to India from US via London and not changing airport.

Do I need transit visa in this case ?
Also I am not sure if I need to go through UK border immigration or not if I am at same airport and same terminal.

I have valid Canada visa also till 2018 so can I be exempted?

Does valid US visa means H1B petition or stamping as some websites say that if someone has valiud US H1B visa they dont need UK transit visa.

So I want to know only when I go back to India when I come back then I would be having new stamping again.

I have already booked my tickets so can someone pls reply me asap and also what visa I need in this case and how much processing time it takes.
My tickets are for 12th dec 2015 .

Thanks for your help.