Martin Johnson has been given a deadline of Monday week to indicate whether he wishes to continue as England manager in the wake of his side's failed World Cup campaign. The mood at Twickenham is also hardening against the players, whose off-field conduct during the tournament is to be investigated. Some have been warned they could face suspension from England's Six Nations campaign as a result of their behaviour in New Zealand. Johnson's role as manager is now under fresh scrutiny in the form of an independent review led by the former England prop Fran Cotton, commissioned by the Rugby Football Union's acting chief executive, Martyn Thomas.

This latest development also increases the pressure on Rob Andrew, who indicated at the weekend that he would be effectively deciding Johnson's fate. It now appears the positions of both himself and Johnson are under increasing threat.

Thomas said the off-field headlines surrounding the squad had been "wholly unacceptable" and said the RFU's legal officer, Karina Vleck, would be "investigating all the allegations of misconduct off the field". Among the possible sanctions would be fines or suspensions for breaching the code of conduct agreement all the players had signed up to.

Johnson's future is likely to be the first issue decided. "It's not his decision whether he remains in the post, I want to make that clear," said Thomas. "I've given him seven to 14 days [from the day England flew home] to advise me of his position. What I need to know is if he wishes to be considered for appointment on 1 January. That's not to say he will or will not be appointed.

"If Martin walks and we have to appoint a temporary coach for the Six Nations, that's fine. We've wasted a lot of time since 2003. I really want to make sure we get this right this time. We've got to take stock and do this right. I spoke to Martin immediately after the game He was pretty upset and it wasn't the moment to discuss the future with him."

Cotton, a one-time RFU vice-chairman as well as Lions prop, has already been vocal in his criticism of Johnson. He will lead a two- or three-strong panel likely to include a member with no current rugby connections. Johnson's contract expires on 31 December and, though he led England to a Six Nations victory in the spring, the World Cup campaign in New Zealand was a disaster on and off the pitch, the quarter-final defeat by France last Saturday following a series of embarrassing disciplinary incidents. "We've had internal reviews in the past and I don't think they are the solution," said Thomas.

Cotton told Sky Sports News: "Martin has now been in charge three and a half years and it is very difficult to understand what style of play this England rugby team is all about. The basic skills of rugby at that level just aren't good enough and I haven't seen an improvement. The players have got to take a huge responsibility. When they go on the pitch they are in charge of their own game and it was very obvious in this World Cup that there seems to be a lack of leadership."

Cotton's team will be charged with reviewing the performance of the RFU's professional rugby department and assessing Andrew's report into the World Cup campaign. The independent panel will undertake its review in November and make recommendations to the RFU's management board and the council on 2 December.

Andrew announced after the France defeat that he had accepted the new position of professional rugby director. That role was created to oversee the whole England set-up and the RFU's relationship with Premiership Rugby and the Championship but the appointment is yet to be formally approved. Cotton's panel will have the power to recommend who should lead the professional rugby department.

The fact that Andrew is not a guaranteed choice will also open the door to the possibility of Sir Clive Woodward returning to Twickenham. Martyn Thomas's backing of Woodward led to the departure of John Steele as chief executive early last summer and the fall-out has led to fresh calls from clubs for Thomas to follow him.

The latest initiatives mean there are now five different reviews being undertaken into different aspects of the RFU's management. It may be difficult to bring fresh disciplinary charges against players whose cases have already been dealt with. Manu Tuilagi has already been fined for his ferry jump and three players were officially reprimanded following an alleged incident in a Dunedin hotel. The ball-swapping saga also resulted in two members of England's back-room staff being suspended for one match.