The Bayesian sank during freak weather early on Monday some 700m off the coast.

It is thought to have been struck by a tornado over the water - otherwise known as a waterspout - which caused the vessel to capsize and sink 50m (164ft) to the seabed.

A steady stream of boats was seen going in and out of Porticello throughout Wednesday, ferrying divers to and from the search site.

Dozens of emergency services staff had lined the small quayside as the bodies of those missing were returned by boat from the area of the wreck.

One body bag was seen being put in the back of an ambulance before the sound of sirens filed the harbour and the vehicle, escorted by two police cars, left the port.

Italian authorities have so far declined to identify those recovered, despite reports from local and international media on some of their names.

This is likely because they are waiting to bring back all six bodies before contacting the victims' families and according to Italian law, the deceased must be formally identified by a family member, or a person close to the victims, before the deaths can be officially certified.

Earlier, the head of Sicily's civil protection agency Salvatore Cocina said there would be an investigation in due course, but the priority was to find everyone who was on board the Bayesian vessel.

Neda Morvillo, an American jewellery designer, and her husband Chris are also among the missing.

The Bayesian, 56m long and flying a British flag, was carrying 10 crew and 12 passengers when it sank.

Of the 22 people on board, 15 survived - including aBritish mother who described holding her baby girl above the surface of the sea to save her from drowning.

The body of the yacht's chef, Canadian-Antiguan national Recaldo Thomas, was found on Monday.

Gareth Williams, a friend of Mr Thomas, told the BBChe had known the chef for 30 years as they had grown up together in Antigua, where Mr Thomas lived during yachtings off-season.

The passengers aboard were guests of Mr Lynch - founder of the software giant Autonomy - and were reportedly there to celebrate his acquittal in a massive US fraud case.

Mr Lynch was acquitted in June of multiple fraud charges relating to the $11bn (£8.6bn) sale of Autonomy to the US computing giant Hewlett-Packard in 2011.

Inspections of the yacht's internal hull also took place on Wednesday morning, while a team of four British inspectors from the Marine Accident Investigation Branch (MAIB) arrived in Sicily on Wednesday at the site.

The depth of the shipwreck has proved challenging for the rescue effort.

Italian rescue services said the team of specialist divers had been hampered by the fact the Bayesian is lying on its side at the bottom of the seabed, with its access points choked with debris.

Speaking before the bodies were recovered, professional diver Andy Goddard said conditions would be "pretty dark" on the wreck with very limited ambient light at that depth.

"You're in this space and you've got stuff floating all around you, like being in a washing machine. It's really dangerous for the diver," he told BBC Radio 5 Live. (BBC)

Rescue personnel transport a body after a luxury yacht, which was carrying British entrepreneur Mike Lynch, sank off the coast of Porticello