As a lot of readers find this post directly via a search engine, I would also like to say Welcome and to say that if you have ANY interest at all in Avios, air miles or hotel loyalty points then please stick around – there is a lot for you here!)
Back in the olden’ days (ie pre 2013), you could always rely on the internet to find you a nice promotional code to reduce the cost of your Heathrow Express ticket ….
From the start of 2013, though, all of the discount codes except one (for Air New Zealand) stopped working. And then, at the end of January, the Air New Zealand code died as well.
Some group saver tickets are still available – see this post for details - but nothing for single tickets.
However, Flyertalker monkeymagic has unearthed a working Heathrow Express promo code – targetted, wierdly, at the Spanish Chamber of Commerce in Great Britain!
The link is here (EDIT: link removed as now dead)
It gives 10% off economy and First Class tickets, taking a single economy ticket down from a ludicrous £20 to a only-slightly-less-ludicrous £18.