Richard Branson’s Virgin Group has said there are “no more major hurdles to overcome” before it can begin operating passenger trains through the Channel tunnel after a decision by the rail regulator.

The company, owned by the billionaire entrepreneur, made the claim after the Office of Rail and Road (ORR) said some capacity at Eurostar’s Temple Mills maintenance depot in north-east London could be made available to other operators.

Access to a suitable depot for maintaining and storing trains has been cited by the industry as a critical requirement for companies to compete with Eurostar.

Virgin, which previously operated intercity trains in Britain including between London and Glasgow, plans to start rail services connecting the UK capital with Paris and Brussels. It also hopes to run trains to Amsterdam. Earlier this month it said it was raising £700m to fund the plan.

The ORR made its statement after receiving an independent report it commissioned to investigate the issue. The regulator said: “Eurostar’s London depot would be able, if required, to accommodate additional trains.”

It added: “Changes to operational and maintenance arrangements at the depot, as well as possible alterations to infrastructure, would be required to access extra capacity and allow more trains to be stabled/maintained there.”

Eurostar holds a monopoly on running passenger services through the Channel tunnel, which opened in 1994.

A Virgin Group spokesperson said: “Finally a green signal for competition. The Temple Mills depot is the only facility in the UK which can accommodate European-style trains and claims suggesting it was at capacity have been blocking Virgin from coming to the line.

“Virgin is therefore very pleased with the outcome … There are no more major hurdles to overcome.” It added: “We expect to be able to make an announcement very soon.”

Virgin Group was the majority owner of Virgin Trains when it ran domestic services on the west coast mainline from 1997 to 2019.

Gemini Trains, chaired by the Labour peer Tony Berkeley, and the Spanish startup Evolyn, are also hoping to run trains through the tunnel.

Andrew Meaney, a partner at the economics and finance consultancy Oxera, which is advising Gemini Trains, said: “Gemini welcomes that the ORR’s transparent process has determined there is available capacity at Temple Mills international depot and we look forward to working with them as they use their duties to allocate this capacity.”

Eurostar said the OOR-commissioned report “confirms” that the depot was “effectively almost full today for major maintenance work and would require investment to meet the growing demands of international rail”.

It added: “The options presented in the report could help create some capacity, but this would not be enough to accommodate the stated ambitions of any single operator.”

Separately on Monday, Network Rail’s boss, Andrew Haines, announced his retirement amid a government overhaul of the sector. He will leave the company in October after seven years in the role.

The functions of Network Rail, which manages railway infrastructure, will be taken over by Great British Railways, a new state-owned company. The government is consulting on policies to be included in the forthcoming railways bill that will enable the establishment of GBR. Thousands of jobs could go as part of the planned shake-up.