Transit Visa For Uk For Travel Via London

[ramadiwakar]

Hi,

I am going to travel from USA to INDIA via LONDON and return to USA. My itenary includes

(1) CHICAGO - LONDON HEATHROW - HYDERABAD - onward
(2) HYDERABAD - LONDON HEATHROW - CHICAGO - return

I am holding a valid H1B visa.

In the return journey my family is going to accompany me. They are also going to have valid H4 visa. I am not changing the airport at LONDON.

I would like to know if I need to take a transit visa in either direction of travel via LONDON ?

Thanks in advance