The Dutchman has signed a three-year deal at the Amsterdam ArenA to replace Marco van Basten, who resigned with one game of the Eredivisie season remaining after missing out on a Champions League spot.

Jol spent one season as Hamburg coach and led the club to fifth place - and a Europa League spot - in the Bundesliga.

He also guided the club to the semi-finals of the UEFA Cup, but Hamburg chairman Bernd Hoffman and sporting director Dietmar Beiersdorf were prepared to tear up his contract.

"The developments of the last few days were very surprising," Hoffman told the club's website.

"We had many conversations. At the end of them we realised it would be for the best if we went our separate ways."

Jol had one year remaining on his Hamburg deal, but Hoffman said the club saw no reason to demand compensation.

"We have not asked Jol to fulfil his contract until 2010 because Ajax have offered him a longer-term deal with more far-reaching powers. He has better prospects there," he said.

Beiersdorf added: "We simply had different ideas."

Hoffman revealed the disagreement between Jol and the club was over the direction of transfer policy, suggesting the coach wanted to spend more than the board were prepared to authorise.

"It is in the interests of the coach to want the best players available," he said.

"We also have the same idea. But you can only take as many risks as you can justify economically.

"We have invested a lot on the team in recent years, and we will continue to do so."

Beiersdorf thanked Jol for a "great season", while Hoffman added that the search will begin immediately for a replacement.

"We have a chance to plan early and set a course for the future," he said. "The new coach will have a full transfer window to work with. We know the market for coaches and we know what we want.

"We have a very good job to offer so we will find a new coach soon."

Ajax were delighted to get their man.

"It is the most important position in a football club so we gave it very careful consideration," said the club's chief executive Rick van den Boog.

"Martin has all the qualities the new coach of Ajax in our view should have.

"He is experienced both domestically and abroad. He has worked in large and smaller clubs and got the maximum from his players.

"He is a trainer who has shown that he gives talented young players a chance - our basic interest.

"I am very pleased with the way we have worked to achieve this. It was an exciting and challenging period, with an excellent result for Ajax."

Jol, who last worked in Holland with RKC Waalwijk before moving to Tottenham to take up the role of assistant to head coach Jacques Santini in 2004, is relishing a return to his homeland.

He said: "Ajax gives me a great opportunity with an eye for the long term.

"I get a very wide array of responsibilities. Ajax is a fantastic club and I very much want to get started.

"I enjoyed my stay at HSV. It's a great club and Hamburg is a nice city to live and work in. I have in recent years worked abroad and once again return to the Netherlands, so I very much look forward to this."