Billionaire's £12m party for 600

Packaging billionaire Hans Rausing, one of Britain's richest men, is throwing a £12 million party today - treating 600 friends to a Mediterranean cruise with entertainment from Sir Elton John, Simple Minds singer Jim Kerr, and the entire cast of the hit West End musical Umoja.

The preparations have been shrouded in secrecy until now. Insiders told the Evening Standard that the event easily outshines Bhs boss Philip Green's spectacular £5 million Cyprus toga party in March.

It has been planned with military precision by a London entertainment agency but it is still unclear why Mr Rausing, 76, has decided to throw the bash - his birthday is in March. One thing, however, is certain: no expense has been spared.

The guests, including designer Giorgio Armani, are being wined and dined aboard the Seven Seas Mariner, one of the most spacious cruise ships in the world, which has been hired by Mr Rausing for the week.

They boarded the ship in Cannes on Sunday. By day they enjoy aromatherapy, massage, steam room and sauna sessions, golf, swimming and tennis on the sports deck. By night they are offered first class entertainment.

Last night Sir Elton performed a selection of his greatest hits on board. Tonight there will be a oneoff performance of the hit show Umoja, which was forced to end its run at the Shaftesbury Theatre in February after noise complaints. The performance is at the ancient amphitheatre in Taormina, Sicily.

The cast, crew and set have been flown in from South Africa, where they were staying until the start of a new run at the Queen's Theatre next month. Show producer Joe Theron said: "I got a call from an agent in London asking us if we wanted to put the show on in Italy. I said yes straight away.

"They told me it was only for one night. I said: 'You are never going to make any money by putting on a show like this for just one night.' The woman then informed me that it wasn't about making money, it was just about entertaining people."

Mr Theron said: "This is an unbelievable operation. All those involved in the production have been put up in one of Sicily's most exclusive hotels. We are having an amazing time and being paid well for it.

"I didn't know much about Mr Rausing before, but he clearly has a lot of money to spend. The cost of bringing our show here alone must have cost £150,000. Add to that the fee for someone like Elton John, then all the costs of staff, food, drink and other entertainment on the boat, and you are talking millions of pounds and one hell of a good party."

Swedish-born Mr Rausing is worth £4.5 billion. His father invented the carton now used by millions of people for storing milk and other drinks.

The family firm, Tetra Laval, is one of the most profitable in the world. Mr Rausing ran the firm until 1993, but two years later sold his stake to his brother Gad for £4.3 billion. He has been resident in Britain since 1982, living in East Sussex.