From relevant London, take the Piccadilly Line quickly to Heathrow Terminals 2&3, four, or 5

https://www.mediafire.com/file/rxghn0zxxeyihtb/pdf-78121-57769.pdf/file

From primary London, take the Piccadilly Line straight away to Heathrow Terminals 2&three, 4, or five. Trains run ordinarilly and are budget-friendly.