Watford boss Adrian Boothroyd has no doubts that England international Ben Foster will dethrone Edwin Van der Sar of his first-team spot at Manchester United coming season, and has exhorted that the youngster can become the best goalkeeper in the world.

23-year-old Foster will return to Sir Alex Ferguson’s Red Devils in summer, following a successful two-year loan spell with the Hornets.

"Ben is a terrific player," Boothroyd said.

"He has such a presence and an ability to start attacks, whether it's on a counter-attack with his long throws or whether it will be lofting a ball down the side for somebody to run onto.

"Even when the back pass comes to him from one side, he can drop the ball onto somebody's feet on the other side. He has exceptional talent, and we are going to miss that.

"If you asked him, he'd tell you he could play centre forward or left wing, but I think he's best where he is. He's part of the team and has a great humility about him.

"He recognises the fact he's just a cog in the wheel. He works harder at his game, and that's why I think he'll be a future Manchester United and England number one.

"I'm sure he will be back at Manchester United next season. He's better than Edwin Van der Sar in my opinion, but then I'm not picking the Man Utd team.

"He is going to be the best goalkeeper in the world, I'm convinced of that."