Paddington, the West End and the City need different answers
Heathrow Express is the fastest direct airport train to Paddington, with Heathrow currently publishing a 15-minute trip from Terminals 2 and 3. The Elizabeth line takes longer to Paddington but continues directly to Bond Street, Tottenham Court Road, Farringdon and Liverpool Street, which can remove a second transfer.
The Piccadilly line is slower but goes directly through central-London areas such as King’s Cross St Pancras, Leicester Square and Piccadilly Circus. That can be simpler than taking a faster train to the wrong side of central London.

