The Heathrow Express is selling Express/Standard Class tickets for £15 (£29 return) during October. When booking use the offer code OFFER15, and the discount applies for the first 500 tickets per day, when purchased 7 days in advance.

You can only book 2 tickets per person. No upgrades to First Class are available. Rules for use include the following:

1. Travel must be within three months of date of travel specified on ticket.
2. Single tickets are valid for one journey within three months of the date of travel specified on ticket. The outward portion of the return ticket is valid for three months from the date of travel specified on ticket and the return portion is valid for one calendar month from the date of the outward journey.

Usual prices are £21 one way and £34 return when purchased in advance of travel. On board it is £26 single and £39 return.