The owners of the Scillonian ferry have apologised for leaving hundreds of people stranded on the Isles of Scilly for four days after she broke down during service.

More than 800 people were unable to make the crossing back from the islands after the Scillonian III had to be escorted back to Penzance on Wednesday when she suffered an engine breakdown en-route.

Initially powered by two engines, the passenger ferry returned to port powered by just one engine.

It was not until yesterday afternoon that passengers who had been due to travel back to the mainland over the subsequent four days were able to start making their return journey, once repairs had been completed.

The ferry left Penzance at 3.30pm yesterday to arrive at St Mary's at around 6.15pm, to begin the process of recovering people.

A double sailing is due to take place today, to help speed up the process.

The ferry was due to leave Penzance at 6am today to arrive in St Mary's at 8.45am, ready to leave on the first of today's two crossings at 9.30am.

A second sailing is then due to leave the islands at 4.30pm, arriving in Penzance at 7.15pm.

Isles of Scilly Travel, which runs the service, said: "We apologise for the inconvenience caused and thank you for your patience."

In an earlier statement the company explained that there had unfortunately been insufficient seats to accommodate all disrupted passengers on Sunday.

It would therefore systematically allocate seats onto those sailings to those passengers who had been delayed earlier.

The company has also thanked residents and businesses on Scilly for their support.

"We’d like to praise residents and businesses on the islands and our own team members for the way they have pulled together in what have been unprecedented circumstances to deal with the issue and support passengers," said the owners.

Additional Skybus flights between St Mary's and Land’s End airports were also run, to move as many passengers as possible by air.

There were 34 additional Skybus Islander and Twin Otter flights between Thursday and Saturday evening , with approximately 700 additional passengers that were due to have sailed were transferred via scheduled or additional flights.

A further 18 flights were scheduled for yesterday.