A Channel ferry crossing has been plunged into fresh uncertainty after French authorities said it could stop subsidising the link.

The Newhaven-Dieppe ferry crossing supports 500 jobs in Sussex but has cost French taxpayers €231 million over ten years.

A senior French official has warned the route cannot continue to depend on the massive public subsidy.

Meanwhile 50th anniversary celebrations of the route were postponed amid a struggle to find a new operator beyond 2015.

The Transmanche ferry route is currently run by DFDS Seaways but its contract expires next year.

The tendering process was plunged into disarray earlier this year after the only bid by MyFerryLink was rejected.

The General Council of Seine-Maritime (CGSM) which subsidises the link is looking for new investors.

It has commissioned a study by Ernst and Young into its continuation and economic viability, due to report back in June.

Nicolas Rouly, new president of the CGSM, said: “I wonder about the relevance of a link that depends solely on public funds.

“This is a potentially difficult decision to take to stop the line. But we have spent €231 million of public money in ten years.”

Mr Rouly called on DFDS Seaways to clarify its ambitions after it said it could not fulfil the contract.

Last year The Argus reported that Newhaven Port could close with the loss of more than 500 jobs after French officials threatened to withdraw funding for the crossing.

But the statement was dismissed as a ploy to persuade English authorities to contribute to the route which would be forbidden under the UK interpretation of EU law.

Users of the line have reacted with dismay at the new threat.

Roger Hudson, of Eastbourne, said: “Our government is pouring billions into already saturated rail transport alongside private initiatives yet ignores routes like this that relieves the burden on rail and the inadequate road network.

“It would be a disaster for Sussex passengers and businesses if this line were to close - it is the most direct route from London and the South-East to Paris and western France for both commercial and domestic users.”