Alan Kempson, Nigel Hodges, Sean Woodall and Ricky Every's plane went missing on an exploratory visit for a property company, Worldwide Destinations, which has an office in St Neots.

Mr Kempson, 46, and Mr Hodges, 52, are both directors of a finance company called Diamond Lifestyle Holdings (DLH), which is based at Hinchingbrooke Business Park, in Huntingdon.

Officials in Brazil called off the search after five days of scouring an area of more than 9,000 square kilometres (3,475 square miles).

But relatives of the four businessmen have rented a private boat and sonar equipment to continue searching in deeper waters, and the families have not given up hope.

Speaking from his home in North Petherton, Somerset, Nigel's son Dominic, 22, said: "Dad was an amazingly fit chap and we will always hold out for some hope that he is swimming across the Atlantic now and is on his way home.

"There is always a glimmer of hope."

He said his father, who has run four London Marathons, was a "pretty good swimmer".

Earlier this week, rescue workers found part of the wreckage of the twin-engine Cessna off the southern coast of the state of Bahia.

Air Force Lieutenant-Colonel Beatriz Dellamora said the search was called off on Tuesday night.

The Foreign Office said: "Brazilian authorities confirmed that wreckage from the plane was found washed up on a beach 90-95km (56-59 miles) north of Ilheus and 22km (14 miles) north of Itacare on May 3.

"The Brazilian air force carried out a search operation using one helicopter and two fixed-wing aircraft, focusing on the area close to the wreckage, following tidal patterns since the plane's disappearance, for five days.

"They have now confirmed that they have called off the search after five days and that no further wreckage has been found in that time.

"The families in Brazil and the UK have been informed."

The wife and son of Mr Hodges - the only one of the four based in the UK - flew to South America to join the search.

Maureen and Elliott Hodges, 25, left two other sons, Dominic and Christian, 20, and daughter Gabrielle, 17, awaiting news at the family home.

Dominic Hodges said yesterday he had been expecting the search to be called off.

He said his mother was "desperate to get back" home to see the rest of the family.

Mr Hodges was one of a quartet flying in the twin-engine craft while on a business trip to investigate a potential housing development by Mr Woodhall's firm, Worldwide Destinations.

Mr Every lives in Brazil and is believed to work for Worldwide Destinations from there.

The international marketing and development company, which has its headquarters in Malaga, Spain, and a UK office in St Neots, Cambridgeshire, says it specialises in creating luxury property developments in emerging markets.

It was reported at the weekend that trading in Diamond Lifestyle Holdings, a sub-prime mortgage company co-founded by Mr Kempson with Mr Hodges as finance director, was suspended by the London Stock Exchange (LSE) amid reports that it was suffering from the credit crisis.

Mr Kempson is also said to be a close friend of former prime minister Sir John Major.

The flight was operated by Aero Star, a small charter firm based in Salvador, Bahia's state capital.

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