The Piccadilly line faces major disruption on both Saturday and Sunday, with certain sections of the route completely closed as Transport for London carries out planned upgrades. The biggest change will see no Piccadilly line trains running between Cockfosters and Heathrow from around 4am until the end of the service on August 1 and August 2. There will also be a complete closure of the entire Piccadilly line overnight between 12.30am and 4.30am on the weekend. The entire Tube line is set to be shut for engineering works (Credits: Getty Images)Passengers are also being reminded that westbound Piccadilly line trains are not stopping at Barons Court while upgrade works continue. District Line : Westbound trains will not call at Barons Court until November.