On Mar 15, 3:54*pm, joelpk wrote:
Thanks to all

Will the cellphones work in the underground stations and on the tube?

Not on the London Underground/ Tube i.e. the Piccadilly Line, no -
unless mobile coverage has been installed recently at the Heathrow
tube stations which I'm not aware of. (Note that a good stretch of the
Piccadilly line into central London is above ground - specifically
from Hounslow West to Barons Court - so you'd be able to get mobile
coverage there.)

Mobile phone coverage is however available throughout the Heathrow
Express/ Heathrow Connect stations and tunnels - i.e. the route of the
'free transfer train' between the terminals. (Do note that this is
only free to use between the various Heathrow terminals!)