Avanti West Coast paid out £20.3m in delay compensation to passengers over three months this summer, with the operator on track to pay out more than £70m this financial year, according to Department for Transport figures.
The £9.3m repaid in the four weeks to 25 July matched Avanti's annual profits for each of the past two years. The operator paid a further £12.2m in the following eight weeks.
Avanti accounted for 27% of the £150m total passenger compensation paid across Britain's railway in 2024-25, the largest single operator payout. GWR paid £29.7m and LNER paid £28m in the same period.
Compensation claims across Great Britain's railway reached 9.1m in 2026, up almost 10% year on year, with 80% approved. Most operators now resolve more than 99% of claims within 20 days.
Avanti compensates passengers for delays of 15 minutes or more, paying 25% of fares back. The operator attributes only 23% of its summer delays to its own operations, with Network Rail, other operators and external factors such as trespassers responsible for the majority.
GWR attributed its increased payouts to "repeated heatwaves" causing track defects, points failures and train cooling issues. Fewer than half of Avanti trains ran on time in July, with passengers delayed by an average 19 minutes.
Avanti is due to enter public ownership next year as part of Great British Railways. Under current contracts, train operators receive income from Department for Transport fees rather than fare revenue, with taxpayers absorbing losses from refunds.
A Department for Transport spokesperson said it was "acting to tackle the root causes of disruption" and that under Great British Railways it would make compensation claims quicker and easier through a unified service.