Foreign Secretary Boris Johnson said Sir Michael had "a record to be extremely proud of" as Defence Secretary.
Mr Johnson told the Press Association: "I've known Michael for many years. He has been a great colleague and a great Defence Secretary.
"In his time as our Defence Secretary, he has helped to reduce Daesh in Syria and Iraq by about 90%, he is responsible for the production of, I think, the two biggest ships this country has ever built - two great aircraft carriers - and he created a situation in which the budget for defence will continue to rise over the next two years.
"He has left our great armed services in very good shape as we go forward to build global Britain. I think he has got a record to be extremely proud of."