transit via london - will expired US visa be ok?

[econair]

I have read many recent queries and replies on the topic regarding transit through UK while traveling from US to India. So, I apologise for beating a dead horse.
But more recently a travel agent insisted that one should have a valid (unexpired) visa stamp on passport (Indian national) to be able to fly through London/ other UK airports.
When aksed whether the I-797 Notice of Action (H1-B approval) will suffice as documentation, the travel agent said that nothing short of a stamped and current US visa is required to be able to transit through UK.
Please shed some light based on your experiences/ knowledge on this issue.
Thanks

[txh1b]

You need a transit visa. Look at immihelp homepage for more details.

[rajarampande]

Transit in london

I hold a US green card and Nepalese passoport . I am travelling through Heathrow airport. I have 10 hrs layover. My flight lands in terminal 3 and i am planning to use Yotel rooms in terminal 4, and thena agin take a connecting flight from terminal 3, which looks like i need to take a bus to get to terminal 4 from terminal 3, do i need a UK visa for this? any info on this will help.
Thanks
RajaRam

[txh1b]

I think you don't need one due to your GC. However, confirm it by calling the UK Consulate in US as Nepal does not appear on the list here.

https://www.immihelp.com/non-usa-transit-visa/