Heathrow’s owners are demanding the new Crossrail London rail link helps it pay for a stretch of line it funded that links its terminals to Paddington.
The line, completed 20 years ago, is 5.3 miles long and cost £1 billion and is used by the UK’s most expensive train service, the Heathrow Express.
According to reports the airport wants to recoup the cost of building the line from Crossrail, which could add £40 million onto the annual bill of running the new rail service.
The dispute has put Heathrow’s foreign owners on a collision course with the Department for Transport and Transport for London.
If Heathrow wins the cost would either have to be borne by travellers using rail services to Heathrow or spread across the capital’s transport network.
Heathrow is said to want to recoup the costs with a £597 fee and £138 maintenance charge for each Crossrail train that uses the tracks.
The DfT said it was opposed to increased charges for train operators to access the Heathrow spur.