Wales boss Warren Gatland has sung the praises of England hooker Dylan Hartley - four years after questioning his temperament.

The Northampton captain, whose career has been riddled by disciplinary issues, is expected to start for England in Friday night's eagerly-awaited RBS 6 Nations opener against Wales at the Millennium Stadium.

Gatland was critical of Hartley ahead of the corresponding fixture in 2011, claiming "he has always got a lot to say" and that "he went to pieces" during a club game against Leicester.

Gatland, though, selected Hartley for the 2013 British and Irish Lions tour of Australia - a trip he subsequently missed due to an 11-week suspension after he was sent off in the Aviva Premiership final for verbally abusing referee Wayne Barnes.

Speaking on Monday, the Wales head coach said: "Dylan brings an edge to the game. That's what makes top players.

"I spoke to Dylan when we were at Twickenham, and we had a good chat about the Lions. I would have loved to have worked with him.

"I've got a huge amount of respect for him. He's got an edge and is competitive, and he has that will to win.

"He has improved his game and is a quality hooker.

"I had a few words about him a number of years ago, and he shoved them back in my face and responded brilliantly with a fantastic performance (against Wales).

"As a coach, you have got to admire and respect that. He is a hard competitor, a winner and uncompromising."

England have been decimated by injuries ahead of their latest Millennium Stadium visit, with the likes of Courtney Lawes, Joe Launchbury, Ben Morgan, Owen Farrell, Manu Tuilagi, David Wilson and Geoff Parling among those absent.

Such a lengthy injury list threatens to undermine England's hopes of avenging a record 30-3 drubbing in Cardiff two years ago, but Gatland will not be lulled into any false sense of security.

"Knowing Graham Rowntree (England forwards coach), England will target us up front and will see that as a big part of the game where, if they can dominate and get the ascendancy, it will go a long way towards them winning," he added.

"Given the number of injuries that they have had, they will keep things simple, coming with a physical approach, trying to dominate at set-piece.

"Last year, England went through the campaign and only made four changes in the whole of the Six Nations, and we made 18 and a number of those were forced through injuries.

"Sometimes its swings and roundabouts. They are going through a period at the moment where, unfortunately, they have got a number of injuries, but long term they will look back in six months and say that was pretty beneficial in terms of depth of squad and for their preparation for the World Cup.

"That's the way I would look at it, anyway.

"Everyone is making a lot of the injuries, but it's still going to be a really strong squad."