With Operation Stack tailbacks on the M20 now stretching for 20 miles, rival cross-Channel operators P&O Ferries and Eurotunnel are at loggerheads.

Eurotunnel has been branded “ridiculous” after using Operation Stack to stir up the argument against its ban on running ferry services from Dover to Calais.

The Folkestone-based company was told it must close or sell its MyFerryLink service by the end of July after an appeal tribunal upheld a decision made by the Competition and Markets Authority (CMA).

This week the Port of Dover has seen traffic rocket as Operation Stack has caused chaos across Kent’s roads, following a fire at the Channel Tunnel at the weekend.

Eurotunnel claims this proves the need for more capacity on the Dover to Calais route – which is occupied by P&O Ferries, DFDS and MyFerryLink – despite the CMA arguing the opposite in its ruling.

Spokesman John Keefe said: “Operation Stack illustrates there is room for three ferry operators quite clearly.

“We have always said the market needs that extra capacity for the times when it is stretched and this is a good example.

“January is a time of the year when ferries are taken out of work for maintenance anyway so to get this at a time when there is reduced capacity already is very difficult to absorb.

“If you take three more ferries out of the market, part of Kent would be absolutely girdlocked.

“There is a strong case for extra capacity to be there. That is why we bought the ships in the first place.”

Rival operator P&O Ferries said the Channel Tunnel operator’s suggestions would “bankrupt any ferry operator”.

P&O Ferries spokesman Brian Rees said: “That’s ridiculous. No ferry operator can contemplate having a fleet of spare ships kicking around for when there’s the next blaze in the Channel Tunnel.

“Holding that much spare capacity would bankrupt any ferry operator. It is very strange indeed that Eurotunnel think otherwise.”

“Holding that much spare capacity would bankrupt any ferry operator..." - P&O's Brian Rees

MyFerryLink announced on Thursday its unaudited revenues for 2014 reached €93 million (£71.3m) in its third year of operating, up a quarter on the previous year.

The number of trucks using the carrier last year increased 22% to 399,453, with cars up 7% to 337,654 and coaches up 135% to 265.

Eurotunnel anticipates that within five to 10 years, there will be an extra million trucks coming through the Port of Dover and the Channel Tunnel – an increase of a third.

Mr Keefe added: “If you add another third to the traffic in Operation Stack at the moment, then take out three ships, you can imagine what the effect will be.

“There is clearly a need for extra capacity today and moving forward.”

Disruption is set to continue, with Eurotunnel due to be closed altogether overnight between Saturday and Sunday.

Last year, the CMA ruled Eurotunnel had too much share of the cross-Channel market because it owned both MyFerryLink and the Channel Tunnel.

This, it said, could force one of its competitors to exit the route because there is too much capacity, eventually allowing it to put prices up.

On Thursday, Eurotunnel announced revenues for 2014 grew by 7% to €1.2 billion (£911m).

Its shuttle business also increased by 7% increase, with a turnover of €526.7m (£400m).