The line had to contend with “technical issues” impacting its website booking system shortly after going on sale Monday morning – which P&O said had been caused by “unprecedented demand” from customers.

However travel agents were still able to make bookings via P&O’s trade systems and a spokesperson confirmed the technical problems had been rectified by lunchtime.

A series of three- four- and seven-night cruises onboard Britannia and the line’s new ship Iona will sail from Southampton between June and September.

Prices lead in from £449pp for three nights onboard Britannia and from £1,199pp for Iona’s seven-night maiden voyage.

All guests must be fully vaccinated against Covid-19 to sail.

P&O president Paul Ludlow said the line had hoped its domestic sailings would be popular, “but we have never before seen such significant and immediate demand”, which he believed “certainly shows the effects of lockdown and everyone’s need for a holiday”.

“Many thousands of guests have already made bookings and Iona’s maiden voyage to the Scottish islands is already very well sold and will be a very special cruise,” he said.

Ludlow later added the demand reported by P&O on Monday was “very demonstrable evidence that a holiday at sea, with all that it has to offer, is a popular and much longed-for option this summer”. 

“There’s certainly no other domestic holiday this year which can compete,” he said. “We have spent so long working towards this point and we all just can’t wait to see our ships sailing once again, it’s been a very long year.”