Most people dream of spending £3.25million on a house - but come October wealthy collectors from across the globe will be clamouring to pay that for a car in Battersea.

Billionaire Formula 1 boss Bernie Ecclestone is preparing to take a break from getting the world's fastest cars to race, and will be selling 50 cars from his personal collection.

The Battersea Park sale, being handled by American firm RM Auctions, is expected to make at least £15million for the 76-year-old impresario.

However, the one motor expected to grab all the headlines is his 1937 Mercedes-Benz 540K Special Roadster. Experts believe the vintage car could go under the hammer for as much as £3.25million - which would make it the most expensive Mercedes ever in the world.

The highest price tag ever put on a car was at the Royal Albert Hall in 1987, when a 1930 Bugatti Type 41 sold for a staggering £5.5million.

"Nothing could jumpstart collectors' enthusiasm for this inaugural sale more than the announcement of the Bernie Ecclestone Collection," said RM owner Rob Myers.

"Our London 2007 sale will surely attract international acclaim and garner the attention of the entire classic car world," he added.

The sale will showcase a first-class selection of automobiles from Ecclestone's collection, which he started massing when he had a small business selling motorcycles and second-hand cars in the 50s.

Spanning from important 1930s European classics through to the ultimate cars of the 1950s and 1960s, it will be the first and only time the collection is on show to the public.

Other classics which making up the show will be a 1933 Rolls-Royce Phantom II, bodied by Gurney Nutting; a 1954 Ferrari 250 Europa GT Mk11, and two of the oldest Volkswagen Beetles in existence.

However, even seeing the cars will not be cheap, as only guests in possession of a catalogue costing £50 will be granted entry.

Terry Lovell, author of Bernie's Game, a bestselling biography of Mr Ecclestone, said: "His decision to sell much of his beloved collection is curious. He is 77 this October and perhaps he believes it's time to tidy up some of his private assets."

Visit rmauctions.com for more information on the auction, which is on October 31, and a full list of cars.