Amor has led England's Sevens side to great success

Dawson's retirement left Wasps with only Irish international Eoin Reddan as a recognised first-team scrum-half.

The reigning Premiership champions missed out on Justin Marshall, who preferred a move to the Ospreys.

Amor, 27, who has signed a three-year contract, can also play fly-half but Wasps plan on using him at scrum-half.

He has led England to a hat-trick of Hong Kong titles, a silver medal at the Commonwealth Games and was recently named world sevens player of the year.

"For the last few years I have enjoyed some pretty decent success on the sevens circuit, and that has been a fantastic experience but to come to Wasps is a massive opportunity for me," Amor said.

"I'm aiming to push for a place in the first XV, and I want to take this chance to show people what I am capable of in the 15-man game."

Wasps head coach Shaun Edwards believes Amor's progress will be helped by concentrating on one position.

"Simon is obviously a very talented all-round rugby player who has had an outstanding careers in sevens, but he's also someone who's never settled in one position," said Edwards.

"We're going to develop him as a number nine, where I think he is in the same sort of mould as Eoin Reddan - having great speed to the breakdown and good distribution skills.

"He's also a very tenacious competitor and a valuable addition to the Wasps' squad."

McMillan, 22, was well known to Wasps' director of rugby Ian McGeechan after captaining Scotland at Under-19 and Under-21 level.