Britain's oldest ferry service, The Isle of Man Steam Packet Company, is up for sale with a price tag of around ?100 million.

At least four organisations have joined the race to buy the company, launched almost 175 years ago.

Parent company Sea Containers last night vowed that whoever bought the operation would continue to operate services across the Irish Sea between Liverpool and Douglas.

"We have a 10-year user agreement with the Isle of Man government which guarantees levels of service on the routes. It is a legally binding agreement," said a spokesman for Sea Containers.

The Steam Packet company has, in the meantime, been offered as one of the securities for a ?107 million bridging loan to ensure that Bermuda-based Sea Containers meets a bond repayment due on July 1. A second bond of ?66 million is due in December next year.