Thousands of holidaymakers who have flocked to the Continent for Easter could face huge delays on their return after it emerged P&O Ferries may not start operating vessels again until April 19.

P&O's cross-Channel ferries have been tethered to the dock since the company took the controversial decision of sacking nearly 800 of its seafaring crew on March 17.

Since then, passengers with bookings for its vessels have been diverted to rivals such as DFDS, Eurotunnel and Irish Ferries.

They carried them to France in the expectation that P&O would be back up and running in order to bring them back.

But while many staggered their trips to France, the majority are expected to seek a return over the Easter bank holiday weekend - ahead of the return of schools.

However, that four-day period is traditionally one of the busiest periods and the likes of DFDS says it is already close to capacity.

And that means passengers may struggle to find space on a boat if they had been hoping P&O Ferries would be up and running again between Dover and Calais by the time they were due to return.

The Rail, Maritime and Transport (RMT) union says it understands P&O will not seek to start sailings again until after the busy Easter period.

National secretary of the union, Darren Proctor, told KentOnline: "The information we have is that individuals have tried to book crossings between Dover and Calais and the earliest they are being offered is April 19.

"This doesn't surprise me. The amount of traffic and focus on safety means if they were to run those vessels with a large passenger capacity when a lot of the individuals [crewing the vessels] are not used to working on a RORO [roll-on, roll-off ferry] and not familiar with the crossing, I think it would be problematic.

"I think this is a strategy from the company to minimise any potential risk, so they miss all the busy Easter period."

P&O did not respond when asked to confirm the April 19 date the RMT has suggested.

P&O replaced its experienced on-board crew with agency staff - paid £5.50 an hour.

Rival ferry operator DFDS, which has shouldered much of the burden of stranded P&O passengers seeking to reach France, has already this week said it cannot take any more P&O passengers between April 8-10 - a situation likely to expand into the bank holiday weekend for return journeys.

A spokesman explained: "We will, of course, do everything we can outside the peak weekends to carry as many P&O customers as possible.

"However, our people have for the past couple of weeks been working so hard to handle the extra freight and passengers, so we now see a need to simplify the check-in process and enable our staff to focus on our own traffic - especially in the run-up to the very busy Easter period.

"What we don’t want to do is to create a situation where we have to disappoint customers arriving in the port who we cannot get to France because we are full.

"Right now, we’re doing everything we can to minimise disruption. This includes putting in extra sailings. Yesterday, Dunkerque Seaways returned from her scheduled annual dry dock. Dover Seaways will be back in service later today so we will have a full complement of vessels available for the peak Easter season. We'll keep monitoring the situation and continue to evaluate what more we can do."

Eurotunnel did not respond when asked to comment on its capacity.