England manager Martin Johnson has launched a vigorous defence of Jonny Wilkinson and blasted critics for working to their own agenda.

Wilkinson's position at fly-half has come under scrutiny following England's uninspiring 17-12 victory over Italy on Sunday.

England's World Cup-winning scrum-half Matt Dawson claimed Wilkinson's inability to manage a game and react to situations off the cuff is being exposed without experienced decision makers around him.

Johnson insisted that no player is undroppable but said the whole team must take responsibility for England's disappointing performance.

"I don't agree with the criticism. Jonny missed a few kicks and suddenly everyone is calling for his head, which I find pretty disappointing and surprising," said Johnson.

"No-one is undroppable, no-one ever has been. But is it Jonny's fault we didn't convert our line breaks? No, it's a team thing.

"It has become the vogue to have a pop at Jonny. It is not always right or fair and I think some people are using it for their own agenda but that is the world we live in."

Wilkinson, 30, has only ever been dropped twice by England, for Paul Grayson in the 1999 World Cup and Danny Cipriani in the 2008 Six Nations.

And despite stating that no player is guaranteed his England place, Johnson gave no indication he is planning a change at fly-half.

Wilkinson's understudy Toby Flood is set to be released to play for Leicester this weekend, having been the only unused replacement against Italy in a game crying out for an injection of fresh ideas.

Whatever perceived weaknesses there may be in Wilkinson's game, Johnson insisted selection for any player has to be based on the whole package he brings to the team.

Wilkinson, who has won 75 caps for England, is the leading points scorer in the history of world rugby and his defence is arguably the best of any fly-half.

"You have players who are not in the team who are potentially better at some areas of the game than guys that are in the team. You have to weigh up that overall impact," Johnson added.

"I think Toby has been playing well. We have good depth in that position. We are lucky to have two world-class players at 10."

The chief criticism aimed at England after the Italy game was centred on a lack of ambition as they became embroiled in tedious bouts of aerial ping-pong.

"This match highlighted again that he (Wilkinson) is not comfortable with the responsibility of being the team's playmaker," Dawson wrote in his column for the Daily Mail.

"He can play in the way that has been planned on a flip chart in team meetings but if it comes down to him to work out on the hoof what options to take, more often than not he will kick and miss opportunities to attack.

"Jonny needs players around him, guys like Mike Catt, Will Greenwood, myself or Kyran Bracken, to take decisions, then he will execute them brilliantly."

When asked last week, Wilkinson did not reject the view that he is at his most comfortable playing with a general on his shoulder, barking orders and helping to guide the team around the field.

When England dominated world rugby under Johnson's captaincy, Wilkinson took the plaudits but always deflected the praise towards Will Greenwood or Mike Catt.

Johnson acknowledged England must improve their communication in that area ahead of the Ireland game a week on Saturday, a demand aimed specifically at inside centre Riki Flutey and scrum-half Danny Care.

"We are not playing in isolation out there and that is something we will stress," said Johnson.

"Danny Care is improving all the time in that position and Riki was back for his first game at this level in six or seven months. We can only get better there."

Johnson has kept 17 of his 32-man squad in camp for the next 24 hours - England's starting team from the Italy game plus hooker Steve Thompson and prop Matt Mullan.

Fifteen players have been released back to their clubs for this weekend's round of Guinness Premiership action, including Flood and the six bench players who were used in Rome.

The released players are: Steffon Armitage, Chris Ashton, Matt Banahan, Jordan Crane, Louis Deacon, Ben Foden, Flood, Shontayne Hape, Dan Hipkiss, Paul Hodgson, Courtney Lawes, Chris Robshaw, Dan Ward-Smith, David Wilson, Ben Youngs.