Eddie Jones' future as England head coach will hinge on a "brutally honest" review into the fifth-placed Six Nations finish, says Rugby Football Union boss Bill Sweeney.

But Sweeney has vowed to leave no stone unturned in next month's debrief.

"We have got to have a brutally honest review of how we have gone," Sweeney told BBC Sport.

"Because 2023 is not far away."

The review into England's poor Six Nations has been moved forward from May to April, and will involve a panel of rugby experts both inside and outside the RFU.

But despite describing England's campaign as "massively disappointing", Sweeney has warned against any knee-jerk reaction.

"Out of respect for Eddie I don't think it is fair to start speculating," Sweeney added.

"We must give Eddie all the respect in the world, and the relationship is good enough and open enough for him to say 'This is what went wrong and this is why it went wrong, and more importantly this is how we are going to address it going forward'.

"You have got to recognise and respect what he's done - he is one of the best coaches in the world.

"But in sport that is history - he would be the last person to remind you of his win ratio."

In 2016, Jones said an international coach has a shelf-life of four years, and admitted he stayed on too long in one of his previous roles as Australia head coach.

However while he is now in his sixth year in the Twickenham hot seat, Sweeney says Jones is "very conscious" of not growing stale.

"He certainly hasn't lost any ambition, he certainly believes in the squad and he still knows what has to be done for us to make sure we are on track," Sweeney said.

Despite the majority of his squad being under the age of 30, Jones insists England are going through a period of "transition", something Sweeney has described as "slightly odd."

However the Twickenham boss has defended Jones and the union's obsession with trying to win the Rugby World Cup and emulate the heroes of 2003.

"You look at the impact 2003 had, strong rugby nations tend to be judged on their ability to win Rugby World Cups," Sweeney added. "That is the holy grail."

"Winning a Rugby World Cup is probably the hardest competition in the world to win, but I think the prize at the end is probably worth it.

"I think we've got an excellent chance [of winning in 2023], but we have just got to make sure we are being honest with ourselves and that we are checking it and looking at it and we are convinced we are on the right track."