Despite guiding the Three Lions to the World Cup Finals next summer, still there is pressure on manager Sven Goran Eriksson, with some pundits predicting he will step down after the tournament.
"I think he can do a job like that (manage England)," Gardner told Sky Sports. "Since he has been at Bolton he has progressed the club to extreme measures.
"The club is now so much stronger than when he came and that is all down to Sam. I believe he would definitely be able to move on to the international scene and do the same with England."
Gardner, 27, said: "Sam has done a lot for us here and is doing a great job.
"I wouldn't want to see him go as he has helped my game a lot."