The High Speed 1 line that carries Eurostar trains from London to the Channel tunnel has been forced by the regulator to cut the prices it charges rail companies in a push to open up the route to more operators and reduce fares.

The Office of Rail and Road (ORR) said it hoped the £5m annual reductions in what HS1 Ltd may charge those using its rails up to 2030 will support growth, “including the introduction of new operators”.

Eurostar runs the only international train services from Great Britain, but two companies – Spanish rail firm Evolyn and the Dutch train startup Heuro – are interested in offering rival services amid criticisms of the cost of Eurostar.

The Channel tunnel operator, Getlink, said a year ago that new direct high-speed train routes from London to Cologne, Frankfurt, Geneva and Zurich could be up and running within five years.

Any company operating a service on HS1 must pay charges to access the 67-mile (109km) line. While the owner is a private company, the amount it can charge is regulated because it holds a monopoly.

The ORR said HS1 needed to cut its planned fees by 3.8%, including reducing charges for renewing tracks and stations, including London St Pancras, as well as lowering maintenance costs. The regulator said passengers could also benefit from the lower fees being passed on in the form of fare reductions.

As well as the Eurostar, the HS1 line also handles the Javelin operated by Southeastern, the operator of services in Kent and East Sussex that was taken over by the government in 2021.

There are four stations on the line: London St Pancras, Stratford International, Ebbsfleet International, and Ashford International (although in practice only St Pancras hosts international departures).

However, the ORR said that “it assumes long-term growth in passenger traffic, including the introduction of new operators” on the HS1 line. The watchdog said it is not expecting any freight traffic on the line, but hoped to change that.

Feras Alshaker, the ORR’s director for planning and performance, said: “Our thorough, independent review of HS1 Ltd’s spending plans has resulted in significantly lower costs for passenger and freight train operators using the high-speed line from April 2025. Although, overall, HS1’s original plans were good, the company must now change specific areas of those plans to account for our decisions, which should benefit everyone who uses this railway.”

Mattias Bjornfors, chief strategy and regulation officer for HS1 Ltd, said it was a “positive endorsement for our plan for the next five years” and added that “we now look forward to seeing how the lower cost to operators drives growth on HS1”.

“HS1 has already driven down costs and improved performance by investing in innovative technologies and working with partners to make multimillion-pound savings and reduce train delays,” he said.

“We are now embarking on an exciting period of growth, both domestically and internationally, and further services on the HS1 route will lead to lower charges for operators and significant benefits to the UK economy.”

Eurostar said it welcomed the decision and would invest the windfall on improving customer experience. A spokesperson said: “In recent years, these charges have risen significantly above the rate of inflation, which has put pressure on our ability to invest in the stations and infrastructure needed to support our future growth plans.”