All P&O guests with holidays booked to depart up to 31 July will receive a 125% future cruise credit (FCC), as will all Cunard guests booked on any cancelled voyage. FCCs will be valid for any sailing to the end of March 2022.

Ionafest, P&O’s floating "festival at sea", which had been due to take place onboard new ship Iona from 4 July to tie in with the ship’s naming ceremony in Southampton, has also been postponed.

“With the current lockdown in place and government guidelines around the world advising against travel, it is necessary to extend the pause in our operations for all sailings up to and including July 31 2020," said P&O Cruises president Paul Ludlow.

“We’re so sorry not to be able to give our guests amazing holidays at the moment, but we will do so as soon as global guidelines will allow. Unfortunately these dates also include the much anticipated Ionafest and we are looking to re-schedule that as soon as possible.

“In the meantime, pending more clarity on the longer term impact of Covid-19 and timing on the world’s return to normality, we are considering the evolving advice as well as potential restrictions in ports of call as we look at how and when we phase our ships back into service."

Ludlow added changes to the way the line operates in response to the pandemic would become "the new normal". “We are working hard to make sure that a holiday with P&O Cruises adheres to relevant measures and guidelines to protect everyone on board without compromising our guests’ enjoyment and experience," he said.

"These new stringent measures will be in place as soon as we reintroduce our ships and we will all get used to them in the same way as we got used to airline hand luggage restrictions. They will become the new normal and they will give our guests and crew reassurance and peace of mind.”

New bookings using P&O FCCs must be made by the end of December 2021. However, they can now be used against a second cabin so guests can bring friends or family along, and can be used in conjunction with any desired upgrade.

Guests can also "gift" or "transfer" their FCC by contacting their travel agent or the line if they booked direct.

Cunard, meanwhile, has cancelled all Queen Mary 2 and Queen Victoria sailings due to depart up to and including 31 July, and has pulled Queen Elizabeth’s entire Alaska summer season departures up to and including 8 September.

President Simon Palethorpe said: “These are extraordinary times and this global outbreak continues to challenge Cunard and the travel industry as a whole.

"We would love nothing more than to bring our fleet back in to service, and give our guests the holidays they deserve and long for, but with the lockdowns and travel restrictions in place around the world, this is simply not possible at this time.

“We have been sailing for 180 years and we look forward to many more. We will get through these tough times together and look forward to welcoming our guests back on board again when the time is right.”

All guests with affected bookings will either be contacted directly, or via their travel advisor or agent. Like P&O, FCCscan be used for a second cabin to bring friends and family along, or towards upgrading an existing booking.