English rugby chiefs were today urged to avoid a kneejerk reaction to the disastrous summer tour to New Zealand, with the team arriving back in London still embroiled in a police investigation into allegations of a serious sexual assault.

Two heavy defeats by the All Blacks have become secondary to the fallout from the investigation, which saw four England players refuse to speak, on legal advice, to police about the claims.

The players were allowed to join the rest of the tour party for the flight home but the ramifications of the incident will be far reaching.

Jason Leonard, the former England prop and now a member of the Professional Game Board which controls the game, accepts this could be a defining moment.

But Leonard warned: "I don't believe there will be a knee-jerk reaction because the facts still have to be confirmed. You cannot base any possible action on half truths and Chinese whispers. Obviously, this kind of publicity is not good for English rugby but we don't know where this is going to end."

A new code of conduct will be drawn up for the England squad and there could be an internal Rugby Football Union inquiry headed by Jeff Blackett, their disciplinary officer. Tour manager-Rob Andrew admitted that players could face action, retrospectively, over late-night drinking and inviting women back to the team hotel in Auckland.

He said: "We may have to do that, but at the moment we are being told that any disciplinary action we take or wish to take in the future will have to wait until the official inquiry is finished."

Despite the controversy, England's management held a meeting with senior squad members and agreed to allow players to go out in Christchurch after their 44-12 defeat in the Second Test. Those players who went into the city centre were accompanied by security guards and had to adhere to a 4am curfew.

"Some of the players did go out and we talked about that as a group, whether it was appropriate in the circumstances," said Andrew, England's elite rugby director whose handling of the tour will also be reviewed. "It was the end of a very long 12 months for these guys. It has been a tough experience out here, on and off the field. Some players went out, some didn't.

"Security people accompanying players is something we are going to have to look at to ensure there are no potential incidents. We spoke to the senior players. We are not going to lock them in their rooms after a Test match. Players have got to take responsibility for their own actions, on and off the field.

Martin Johnson, the England team manager, was unable to tour in New Zealand due to the birth of his second child but he now assumes a vital role. It will be up to Johnson to pick his 32-strong elite player squad on 1 July and ensure the summer tour failures do not become a serious problem.

Johnson was one of the key voices when Clive Woodward, the 2003 World Cup-winning head coach, drew up the code of conduct which England followed-under his leadership. There was input from both sides, with the regulations covering everything from personal appearance in publ ic to punctuality for team meetings. Johnson will use that agreement as the template for his first squad.

London Wasps outside-half Danny Cipriani is unlikely to be included due to the five months remaining in his rehabilitation process.

Cipriani fractured and dislocated his right ankle at the end of the season and Andrew said: "It would be very unlikely that we will name a guy who is going to be out for the first six months of the season. But we would have the facility to add him into the squad."