Following a year at Saracens, he moved to Harlequins, where he stayed until his professional retirement in May 2004, making a total of 290 appearances for the team.

Due to brilliant surgery and his rehabilitation regime, however, he made a full recovery, winning his 11th cap against Canada at Twickenham that autumn without missing an England test.

Rowell claimed he would rid England of the cautious, forward-dominated 10-man game which had done so well for them earlier in the decade, and play running rugby more similar to Bath's.

In the 1995 Five Nations, Leonard won a record (for a prop) 38th cap for England,[citation needed] playing against Scotland, and the victory meant his third Grand Slam.

Against Australia, Leonard found himself selected at loosehead prop again, with Wasps' Will Green winning his first cap at tighthead.

England had shown signs of improvement under Woodward, who had been looking to play a more expansive game, but were denied a Grand Slam prior to the World Cup due to Neil Jenkins' boot and a last-minute try by Scott Gibbs.

In the 1999 World Cup, England were drawn in Pool 2 with New Zealand, Italy and Tonga, but were knocked out of the tournament at the quarter-final stage by South Africa.

After this, England began to notch up regular victories against the big guns of the Southern Hemisphere (New Zealand, South Africa and Australia), culminating in the 2003 World Cup.

On 15 February 2003, Jason Leonard became the first-ever forward to make 100 international appearances, when he started against France in a Six Nations clash.

In March, Leonard played a key role in securing England's Grand Slam with a win over Ireland at Lansdowne Road.

In August he captained England for the second time in World Cup warm-up match, crushing Wales 43–9 at the Millennium Stadium in Cardiff.

It was Leonard's proven ability to play both loose-head and tight-head and experience which earned him a spot in England's World Cup Squad.

During the 2003 tournament, Leonard appeared in his second World Cup final as a second-half substitute for tight-head prop Phil Vickery, playing a vital role in reducing England's high penalty count at the scrum.

The then coach Clive Woodward later wrote in his autobiography that Leonard's introduction was the key substitution which helped England to win the match.

In 2014, he founded The Atlas Foundation, which exists to help deprived children around the world work towards a better future through rugby communities and initiatives.

Jason spends an enormous amount of time working on behalf of many other charities to support fundraising and raise awareness for their causes.