Children and teachers returning to the UK from half-term school trips have been hit by delays of more than six hours at Calais amid strike action by Border Force staff.

Members of the Public and Commercial Services (PCS) union working at French ports began industrial action over pay on Friday, with strikes due to continue until Monday morning.

A number of schools reported issues returning from trips on Saturday as parents complained on social media that their children had been stuck at Calais for hours.

Some said their children had been waiting to board a ferry as early as 8.30am, but were still on the French side by the afternoon.

One mother tweeted it had been a “gruelling trip” for her daughter, saying: “Thirty hour journey last week travelling to Austria due to delays and 23 hrs since leaving Austria they are still stuck at Calais! Arrived at about 10.30 this morning.

“Fingers crossed they can get on the 10.45pm! It’s a good job she had a fab time!”

Another parent said: “Although I’m all for strike action, she (my daughter) is not coping well with the delay at Calais. Been travelling since 6pm yesterday and at Calais since noon.”

One woman tweeted: “Is there any further update on the delay time for coaches at Calais?

“My son is returning from a school trip and has been on the coach at the port since 8.30am.”

Wellsway School in Bristol tweeted that students returning from a ski trip had missed their scheduled ferry from Calais due to the long queues for passport control, while Langley Park School for Girls in Bromley, south-east London, said they were making “very slow progress” at the port.

DFDS Ferries said coach passengers should expect six-hour delays at Calais due to “high volumes of traffic”.

P&O Ferries tweeted: “There are still large queues of up to 6hr 30mins at border control in the Port of Calais for coaches.

“There are limited toilet facilities, we recommend stopping en route.

“Please come prepared with refreshments to make your wait more comfortable.”

Car traffic was delayed by up to an hour at Calais earlier on Saturday, but had cleared by the evening.

Last week, Border Force warned that travellers could face delays on arriving in the UK at ports and urged them to check with the operator before beginning their journey.

It added that the military, civil servants and volunteers had been trained to step in, keep borders safe and minimise disruption.

A PCS spokesperson said: “While we sympathise with travellers experiencing delays, the blame lies squarely with the Government. Rishi Sunak has had months to resolve this dispute but refuses to meet us. He can end the strikes tomorrow if he puts some money on the table.

“Until he does, our strikes will continue because it is unacceptable that hard-working civil servants are being told to accept just a 2% pay rise during a cost-of-living crisis when inflation is at 10%.”