Transport Focus says that 35% of passengers claimed £81 million for delays in 2017/18, and that up to £100 million is unclaimed every year.
It says in 2017/18 just 39% of eligible passengers claimed compensation for delays of 30 minutes or more, and only 18% for delays of 15 minutes or more.
The watchdog found passengers didn’t claim because they didn’t know they could, doubted it was worth it or thought it was too complicated.
Transport Focus has now launched a campaign – Make Delay Pay – to encourage more passengers to claim the compensation they’re entitled to.
See our Train Delays guide for how to claim online in under five minutes.