Steve Borthwick has been forced into a drastic reshuffle of his Six Nations squad after Jamie George was ruled out of the opening two rounds, the former captain among four players to withdraw from the England squad.

England are facing a potential injury crisis ahead of their Six Nations opener against Ireland with Jamie George ruled out and Alex Mitchell a doubt.

Hooker George, who has been replaced by Maro Itoje as captain, suffered a hamstring injury playing for Saracens in the Champions Cup and is among a group of five forced to withdraw from a pre-tournament training camp in Girona.

First-choice scrum-half Alex Mitchell, who missed the autumn Tests with a neck injury, could also miss the game with a knee problem he picked up against Munster on Friday

England vice-captain Jamie George has been ruled out of the Six Nations opener against defending champions Ireland on February 1, the Rugby Football Union announced on Tuesday.