The Ukraine forward’s arrival for a fee in the region of €45 million (about £31 million) breaks the British transfer record set by Manchester United when they signed Rio Ferdinand for £29.1 million four years ago. It is a straight cash deal, meaning that William Gallas, the defender admired by AC Milan, will not be moving in the opposite direction.

Shevchenko, 29, signed a four-year contract after passing a medical and agreeing personal terms. After Chelsea’s capture of Michael Ballack, he will add further Champions League experience to a club who have made the conquest of Europe their primary target after winning the Barclays Premiership title in successive seasons, having helped Milan to claim the European crown in 2003 by converting the final penalty in their shoot-out victory over Juventus at Old Trafford.

“I am going from one big club to another and joining a team of champions,” Shevchenko said. “There is a right moment to join a club and I think I have arrived here at the perfect time. The Champions League has to be a realistic target for next season, but it is not just about the Champions League. Chelsea are going for their third Premiership as well and I like the club’s mentality of wanting to win every game they play.

“Had money been my motivation, I would probably have stayed in Milan. I am pleased that Chelsea managed to conclude everything before the World Cup — I can go to Germany with a clear mind and proud to be a Chelsea player.”

Shevchenko’s strike-rate of 53 goals in 94 games in the Champions League takes Mourinho closer to his vision of continental supremacy, but it also pushes them farther away from the stated aim of Peter Kenyon, the chief executive, of making the club self- financing by 2010.

“Today is a day when the dream became reality,” Mourinho said. “Andriy has always been my first choice for Chelsea since I arrived. Milan is a big club, a great club, but for him to leave Milan for Chelsea is a big statement about where Chelsea is. He is a champion and he is joining a team of champions.”

Chelsea will be paying a total of about £500,000 a week in wages to John Terry, Frank Lampard, Ballack and Shevchenko, who will join Ballack as the highest-paid player at the club on £130,000 a week. The spending is unlikely to stop there. Mourinho — reported to have signed Ben Sahar, a 16-year-old Hapoel Tel Aviv forward, for about £300,000 yesterday — is also keen to lure Roberto Carlos, 33, the Brazil left back, from Real Madrid, describing him last night as the best player in that position in the world.

Shevchenko cited personal reasons for his desire to leave Italy after scoring 127 goals in 208 league matches at the San Siro. His wife, Kristen Pazik, an American model, was keen to move to London and the pair — who say they want their son, Jordan, to grow up in an English-speaking country — have already received a warm welcome, with the Chelsea Supporters Group offering her honorary membership and a promise that the shopping in Chelsea is “at least as good” as she is used to in Milan.

Shevchenko, a friend of Roman Abramovich and the owner’s favourite player, takes the club’s spending on transfers to more than £280 million since the Russian bought Chelsea three years ago. The European Player of the Year in 2004 has not played since May 7 because of a knee injury but expects to play in Ukraine’s opening World Cup match, against Spain on June 14.

On the day that Chelsea agreed to spend so much money, Premiership clubs were being praised for their parsimony. The Deloitte annual report into football finance has revealed that the overall top-flight wage bill dropped for the first time, by £26 million, during the 2004-05 season. Chelsea actually led the way, making a saving of £5.9 million — a figure Shevchenko alone will easily earn in a single season.

With Mourinho intending to pair Shevchenko and Didier Drogba in attack and with Salomon Kalou also having joined from Feyenoord for £3.5 million this week, there will be casualties, with Hernán Crespo, Eidur Gudjohnsen and Carlton Cole expected to leave this summer.

Gudjohnsen has been offered to Real as part of a deal for Roberto Carlos, though Chelsea remain keen on Ashley Cole, the Arsenal left back, as another possible replacement for Asier Del Horno.