Matt Williams led Leinster to Celtic League title success

He will take over the job, which McGeechan will vacate after this year's World Cup, on a four-year contract.

Williams described the appointment as a great honour as the news was confirmed in Durban, South Africa where Scotland are preparing to face the Springboks this weekend.

And he described the lure of the post as "irresistible".

"Firstly I would say that I'm honoured to be given the opportunity to coach one of the great sides in world rugby," he said.

"I was very happy at Leinster and the Irish RFU has treated me brilliantly but the lure of Scotland head coach post was, for me, irresistible.

"To follow in the footsteps of Jim (Telfer) and Ian is a very humbling experience and I'm very aware of the responsibilities that have been given to me.

Profile: Matt Williams

"My aim will be to build on the foundations that have been put in place by Jim and Ian.

"Great strides have been made in the last four years in Scottish rugby and my role will be to take that structure forward in all areas from the players, coaches and support staff with the national team down through the age-grade sides."

McGeechan replaces Jim Telfer as the SRU's director of rugby and he admitted he was excited by the appointment.

Telfer added: "In Matt Williams we have found an outstanding young coach who I am sure will prove an exceptional custodian of all the values that are dear to Scottish rugby, while also bringing innovation and plenty of ideas to the national team."

Williams took over at Leinster four seasons ago following a spell with New South Wales Waratahs.

He led Leinster to victory in the Celtic League in season 2001/02.

Matt Williams is a forward-thinking coach who wants to be party to the further development of Scottish rugby Ian McGeechan

The appointment of a non-Scot is likely to divide opinion, according to former Scotland A coach Ian Rankin.

"It is a big decision to make and it will be a pretty tough job," said Rankin.

"But I think there will be a split camp with bringing a non-Scot in. However, Matt is a high quality coach - there is no doubt about that."

Leinster chief executive Mick Dawson admitted the club were disappointed to lose the services of Williams, but understood the attraction of moving to an international position.

Former Ireland captain Willie Anderson, who was assistant to Williams at Leinster, will act as caretaker in the interim.

While Anderson will be in the running to take over on a full-time basis, rumours of Ulster coach Alan Solomons moving across the border are wide of the mark.