Chelsea are one of England's most successful clubs

The surprise takeover - the biggest in British football history - was finalised late on Tuesday after talks with long-time chairman Ken Bates.

He bought the club in 1982 for just £1, while taking on debts of £1.5m.

Although the club has prospered, debts have grown and it is estimated the new owner will stump up £80m to cover them.

On top of that, Mr Abramovich is buying just over half the shares of Chelsea Village, which owns the football club, for 35 pence each - putting the total value of the club's shares at £59.3m.

The Russian businessman pledged to plough even more resources into the club while Mr Bates said the deal would move Chelsea onto the "next level".

"We are delighted to agree this deal to acquire what is already one of the top clubs in Europe," Mr Abramovich said.

"We have the resources and ambition to achieve even more given the huge potential of this great club."

Mr Abramovich is one of the major shareholders in Sibneft, one of Russia's largest oil companies, and "a keen follower of sport and international football," a statement said.

Mr Abramovich also has significant interests in Russia's aluminium industry, and until recently owned a sizeable stake in Russian airline Aeroflot - the sale of which may have funded the Chelsea buyout.

KEN BATES Self-made millionaire from ready-mix concrete Bought a struggling Chelsea for £1 in 1982 In 1985 he wanted to install electric fences to control crowd trouble at Stamford Bridge In 1991 he ran into controversy when it was alleged Chelsea made illegal payments to players - the club was fined £105,000

The TV interests were significant, "as in the modern game today TV rights are what it's all about," he said.

"Football has been in terrible trouble in this country recently - it's clocked up huge debts and the transfer market has collapsed," he added.

"I think what this could signal is the arrival of overseas sugar daddies.

"If this is the start of the super-rich invaders it'll be very, very interesting to see how the fans react to it."

Misgivings

One Chelsea fan told the BBC he was shocked by the news.

"I think it's disgraceful because I always thought that Ken Bates was Mr Chelsea."

And former sports minister Tony Banks said he wanted more information on Mr Abramovich's business background.

"I want to know whether this individual is a fit and proper person to be taking over a club like Chelsea. Until that question is answered, then I'm afraid the jury is out," he told the BBC.

"A sale has been arranged to an individual we know nothing about."

Mr Banks added that he would be raising the issue with sports minister Richard Caborn.

But Mr Bates, who is expected to remain as chairman, said the deal would help the club.

"This is a great deal for Chelsea Village, the club and its fans," he said in a statement.

"In today's highly competitive football market, the club will benefit from a new owner with deeper pockets to move Chelsea to the next level.

"I look forward to working with Roman Abramovich to achieve even greater things."

Over 20 years Ken Bates transformed Chelsea from a club on the brink of going bust into a large public company at the centre of a major corporate venture.

But his ambitious plans for Chelsea Village, an expensively assembled hotel and shopping complex, helped to saddle the club with large debts.

Despite an influx of several foreign players a Premiership title has eluded the club, although they will play in next year's lucrative Champions League.

Chelsea Village shares were up 12 pence at 40p in early trading on Wednesday.