Sir Clive Woodward believes that Stuart Lancaster is entering his most important game as England coach when his side take on Ireland in the Six Nations later today.
The Red Rose have defeated Wales and Italy in their opening two matches of the competition, but face a huge test against Joe Schmidt's men when they travel to the Aviva Stadium.
Woodward feels that there is no greater test of England's World Cup credentials then to record a victory over Ireland, which could pave thee way towards the Grand Slam.
He wrote in the Daily Mail: "This is a massive game for Stuart Lancaster and this England team. So far he has done an excellent job and now has a very exciting team and a squad to match any in world rugby but if he could go to the World Cup as Grand Slam-winning coach it would be absolutely massive for him and the team.
"As we stand, for all his hard work and endeavour, Lancaster has won nothing whereas his opposite man, Joe Schmidt, has won plenty of silverware and is widely regarded as the best coach in the world.
"But make no mistake, if England do win today — and I believe they will — it will make them red-hot favourites for the Grand Slam and allow them to set sail for the World Cup in perfect fashion."
England last recorded the Grand Slam in 2003 and later in the year went on to lift the World Cup under Woodward's guidance.
