Speaking at the Munich Security Conference on Sunday, British Defense Minister Michael Fallon said British troops must stay in Afghanistan in order to prevent millions of Afghan migrants fleeing to European countries.

Britain has 500 troops in Afghanistan who are busy with training Afghan forces.

Fallon warns that if troops pull out there is risk of collapse.

"If it was right to go in, it has to be right not to leave before the job is done as well as we can do it," Fallon told the conference.

"If this country collapses, we here will feel the consequences, very directly. There could be three to four million young Afghan men sent out by their villages to migrate westwards, and they are heading here". Fallon added.

"There are trans-national terrorist groups in Afghanistan that wish us harm at home and here in our democracies. That is why we went in in the first place and those transnational terrorist groups are still there and they still pose a threat," Fallon said, according to The Times.

This comes after the U.S. commander in Afghanistan Gen. John Nicholson asked for thousands of troops to break the stalemate against the Taliban in a senate panel and added that troops were required to train Afghan forces to replace NATO and US troops.