"If we kept the squad we had now, we'd be too old for the World Cup. There is a certain profile of around 28 years of age for a World Cup winning side," the 61-year-old said.

"We have been bringing that down slowly over the last two years and we need to keep accelerating that because the more senior guys keep getting older.

"It's about getting the balance right in the squad between what we have in terms of very good players and 11 good enough to play for the Lions, so they are pretty good players and if they keep their desire and form there is no reason why those guys can't go to the World Cup.

"All of those guys are probably 25 and above as a general point, so we want to bring some younger guys in with energy, risklessness (sic) and desire that will lift the team higher and higher."

Four years ago on England's tour to Argentina, which took place alongside the Lions being in New Zealand, Tom Curry and Sam Underhill were unearthed and the 'kamikaze twins' would be crucial in a side which reached the World Cup final two years later.

Last week the former Wallabies boss spent time with the Under-20s and told them they had a chance to feature in France in 2023.

After a poor fifth-place showing at the Six Nations, where England had six players aged 30 or over, a trimming of the average age is high on Jones' list of priorities with uncapped Harlequins duo Marcus Smith and Alex Dombrandt set to be named in Thursday's squad to face USA and Canada.

"I might put statures of them up in the front," Jones said of Curry and Underhill. "They moved people out of the back row and took their positions, so there is this opportunity for this group of players and that is why it is so exciting."

Some of England's regulars not with the Lions could be rested after a gruelling 24 months, with Ben Youngs and George Ford due to be given the summer off, but Leicester team-mate Ellis Genge and Kyle Sinckler should be involved in the summer internationals.

Jones admitted Manu Tuilagi would need to be assessed after only returning last month from an Achilles injury.

Following a disastrous Six Nations campaign, there was a chance England could have a new man at the helm for the USA and Canada games but an RFU review into the tournament published in April offered its "full support" to the current head coach, who had extended his deal after the 2019 World Cup.

"I made a decision I think I am best coach to coach England, the RFU agreed," Jones bullishly stated.

"They might change their mind, (but) I am absolutely, certainly committed. Coaching, you take the good with the bad. No one wins 100 per cent of Test matches and our record shows we are travelling pretty well in terms of win percentages."

One of the review's recommendations revealed the RFU had decided that external rugby experts will be brought in to "inform all future debriefs to provide additional insight and support" to the England chief.

But Jones added: "In terms of experts coming in, I am asking experts to come in all the time. I spent last Friday with Danny Kerry, England hockey coach, last week at Hull FC. I want the best people involved in England rugby, so I don't see that as any different from what we have been doing."

Jones has invited numerous key figures into England camps or met them, which includes Sir Clive Woodward who has been a vocal critic of late. But the suggestion was the RFU would now decide who the "external rugby experts" would be.

"But I am the head coach and the head coach makes the decision at the end of the day," he insisted.

"I welcome people in, we've had Brian Ashton in, I've had coffee with Clive Woodward and he spoke to me. Maybe he doesn't want a coffee with me now by the sounds of it but I encourage coaches to come in because I want to pick their brains. There is a lot more smarter coaches out there than me."

Talking in the aftermath of Naomi Osaka's decision to withdraw from the French Open due to the furore caused by her boycott of media duties, Jones praised the bravery of the Japanese tennis player.

She had cited mental heath issues behind her reason to not take part in press conferences at the tournament before subsequently pulling out.

Jones said: "The only thing I would say is she has shown a lot of courage to stand up for what she thinks is right and we want our players to have plenty of character too for what they think is right."