Manchester United have completed the signing of Wayne Rooney from Everton in a deal which could eventually be worth £27m.

United will pay Everton an initial down payment of £10m with a further £10m due on August 1, 2005, with that sum rising by as much as £7m, depending upon the 18-year-old striker’s appearances and achievements.

Rooney has signed a six-year contract which will tie him to Old Trafford until 30 June 2010.

“It was a tough decision to leave Everton, the clu I’ve supported and played for all my life,”said Rooney.

“I’m excited to be joining a club as big as Manchester United. I feel this can only improve my career.”

Sir Alex Ferguson said he was delighted to sign the player.

“I am very excited. I think we have got the best young player this country has seen in the past 30 years,” he said.

“Everyone is delighted by this signing.”

Rooney’s representatives, Pro-Active Sports Management could be paid up to £1.5m – depending on the player’s loyalty to United – for their role in the deal.

The England star, who suffered a broken metatarsal bone in Euro 2004, passed a medical on Tuesday to pave the way for him becoming the most expensive teenager in world football.

Bill Kenwright, the Everton chairman, met United chief executive David Gill for talks on Monday as the two clubs met for a Premiership game at Old Trafford.