Brian Ashton has sprung a surprise on his England squad by sending them to work out with the Royal Marines rather than flying out for a training camp.
Jason Leonard (left) leads the players in an exercise in 1999
They will now fly to Portugal for an eight-day training camp on Thursday after four days with the Marines.
Former coach Sir Clive Woodward, who led England to victory in 2003, worked with the Marines a number of times.
Woodward credits the Marines with helping him identify players with the ability to succeed under pressure.
Ashton, who has only had seven matches in charge, has little time to mould his World Cup group, with the final 30-man squad having to be named on 14 August.
England only have two warm-up matches before Ashton must declare his hand and so the next few weeks are vital in setting the right tone.
World Cup-winning coach Woodward has recounted how, after a session in 1999, a Marine officer told him: "There are men in your squad we wouldn't go into battle with.
"It's not about their skills, it is about their attitude and their effect on the team.
"One wrong team player can sap all the energy from the group."
As England built from the disappointment of the 1999 World Cup, Woodward recognised he required a squad full of "energisers" and by 2003 there was "not an energy-sapper in sight".