Neil Back believes Eddie Jones' England have the strength in depth to challenge for a second World Cup title.
Back was part of the England side that defeated an Australia team then led by Jones to claim the Webb Ellis Cup for the first time in the country's history in 2003.
After crashing out of the competition in the pool stage on home soil in 2015, England have enjoyed a magnificent turnaround under Jones.
They have won two Six Nations titles, including a Grand Slam in 2016, and claimed a 3-0 Test series victory over the Wallabies in Australia.
And, as England prepare for a tilt at a third successive Six Nations success, Back is confident England have the squad to dethrone world champions New Zealand in 2019.
"What Eddie and his captain have done over the last couple of years is incredible. They've got a huge belief in each other and huge confidence, which is a massive thing," Back told Omnisport.
"When they are the tunnel they will be thinking 'play to our best and we will win this game', which is huge for any squad.
"We have got tremendous strength in depth and you need that to capture the ultimate prize of the World Cup. You need two or three, or in some positions four-deep in terms of options for each position.
"One thing England have got to learn as a group is if so-called key players - I'm thinking such as Billy Vunipola - if they are out of the side you have got to have that complete faith in whoever comes into the side to replace them.
"I know England squads I have been involved with you have your recognised starters, but if they were not available we would have complete faith in the player coming in. Every player must have that belief and confidence in the player coming in."
There have been questions as to whether Jones is right to stick with hooker Dylan Hartley as captain.
Hartley has found form difficult to come by with a struggling Northampton Saints team, however, Back has faith in Jones' judgement.
"The most important thing is Eddie thinks he is the right man. What you have got to remember is it is difficult to shine when your team is not performing consistently well," added Back.
"The fact is, if you have the ability and belief, it is actually easier to play at international level because you only have to concentrate on your job.
"You look at Dylan's performances under Eddie, he has performed consistently well and that is all Eddie is concerned about.
"Not everyone can play for the top four clubs in the Premiership and if they play elsewhere, they may not shine as much as teams that are winning week in, week out.
"But as long as they are good enough and perform at international level - which Dylan has - then you stay in the side. Eddie recognises his leadership skills and his mental toughness and I think the players recognise that as well."
Join World Cup 2003 heroes Neil Back, Mike Tindall and Will Greenwood at the award winning Wolf Run obstacle challenge in East Sussex on 28th April. Get your pack together with the buy four get one FREE offer - www.thewolfrun.com
Great to be back with the boys again after far too long. Sick-note Greenwood was moaning about his sore achilles, so the team had to carry him as usual. We'll need to do a bit more training to drag him around the course again on 28th April @TheWolfRun#adpic.twitter.com/SCh3ld6oAy-- Neil Back MBE (@NeilBack) January 29, 2018