But while the British army’s role will evolve, “the whole process might take as long as 30 to 40 years,” Richards said during an interview published Saturday.

Richards added that there was “absolutely no chance” of NATO pulling out completely, telling The Times that Britain would continue to do its part in the nation-building effort.

The general’s comments have caused consternation among some British political leaders, who are saying such a commitment is unsustainable.

However in January, Gen. John Craddock, supreme allied commander Europe at the time, offered a rough projection, which resembles Richards’ views.

Craddock, who retired last month, told reporters that he expected U.S. troops to be engaged in Afghanistan for at least a decade, if not longer.

“Maybe not at current force levels, but I think we’ll see a presence there for decades,” Craddock said.