All confused about UK transit visa for US travel

[deshpandehn]

Hello,

I am Indian nationalite doing PhD in France since Nov 2012. I will be travelling to US on J1 visa via Heathrows Airport London (waiting time 3-4 hours). Please guide me if I would require transit/any other VISA from UK Embassy for this travel.

Thanks a lot in advance.

Regards,
Hrishikesh