Saga said three of its four round-Britain cruises onboard Spirit of Discovery were now fully booked after being announced on 29 March.

The line added there was “only limited availability” for its final Great British Isles Adventure sailing departing from Tilbury on 11 July.

The 14-night itinerary includes calls at Falmouth, Holyhead, Belfast, Greenock, Ullapool, Kirkwall, Orkney Islands, Newhaven and Newcastle, before returning to Tilbury – fares lead in from £3,899pp.

Saga is requiring all guests this summer to have had both doses of a Covid-19 vaccine prior to boarding.

Saga Cruises chief executive Nigel Blanks said: “Our guests had told us how much they wanted to get travelling again, and we couldn’t have more proof.

“We’d prioritised guests whose cruises had been cancelled due to Covid by proactively offering them the option to rebook on to the British Isles cruises prior to them going on general sale on 29 March, which a good number took up. Since then, the rest of the cabins have been snapped up.
 
“We put it down to the fact that our guests know that, not only is their safety and wellbeing our number-one priority, as evidenced through our requirement that all travellers have received both doses of the vaccine prior to boarding, but that they will also enjoy an incredible experience on our ships.”