Hi, a little strange query, but I hope local knowledge will help.
I am not flying but parking my car at one of the onsite car parks, bus to the terminal and then using the tube to get into central London(very long and complicated reason I am doing this)
My question is of terminal 1 2 or 3 which is the shortest walking distance to the LHR central tube station.

I had do this before and used to get off the bus at T3 but with the opening of T2 it makes me think , which Terminal actually is nearest to the Tube.(For practical reasons T4 and T5 are not options)

Thanks for any assistance.