Manchester United have unveiled defender Rio Ferdinand as the club's new record signing on a five-year deal for a fee which could reach £33.1m. The Leeds and England star had earlier passed a medical at United's Carrington training complex and was officially presented to the media at a news conference on Monday afternoon. Sir Alex Ferguson revealed the record-breaking swoop ends a six-year chase for former West Ham starlet Ferdinand's signature. "It wasn't going to be easy. It was a hard road and we're delighted to have reached the end of it," said the Reds chief. "Rio has great potential. We're confident he'll mature here into the best centre-half in the world. "We've had our eye on him since he was 17. We looked at his age, nationality, position and potential. After that the decision to sign him was easy." Ferdinand is now the most expensive defender in the world but the 23-year-old insists the price tag will have no effect on him, having experienced the same pressure when he left Upton Park for Elland Road in November 2000. "I'm delighted to be joining. I'm leaving a great club in Leeds and I thank them for going out on limb to start with and signing me from West Ham," said Ferdinand. "Opportunities like this don't come along all that often. I couldn't have sat here and let it pass me by. "The fee has no effect on my mind at all. I never thought in a million years that I'd be playing alongside players like (Juan Sebastian) Veron." Ferdinand, who is expected to make his United debut in the upcoming Amsterdam tournament, added: "I like to thank my family and friends and my agent for helping me make the right decision and I believe I have made that." United chief executive Peter Kenyon said: "The board of Manchester United PLC confirm an agreement has been struck for the transfer of Rio Ferdinand. "The maximum value is £33.1m, £15m payable now, £14.1m in six months, and £4m depending on his performances for Manchester United." Ferdinand travelled to Old Trafford to begin talks over personal terms on Sunday night once Leeds had given the green light for the deal to go ahead. The player is reported to have signed a contract worth £70,000 per week.