AUSTRALIA has made a strong case for Britain to withdraw its troops from Afghanistan by 2018, the country’s defence minister has said.

In a letter to the House of Commons defence committee, Defence Secretary Michael Fallon said Britain had to make a decision on its participation in a “major peacekeeping mission” in Afghanistan.

He said British troops had been deployed to Afghanistan since 2001, but that since the start of the new Afghan war in 2014 there had been “no clear evidence of the effectiveness of the operation”.

Fallon also said Britain would not be able to train Afghan forces if it remained in the coalition.

British Prime Minister Theresa May has argued that Britain should withdraw troops by 2020 but this would require the full backing of the United States.

Fallons letter to MPs also warned of “a significant risk of increased international terrorism” if the UK continued to fight in Afghanistan and warned the “immediate withdrawal” of all British troops from the country would mean the end of international cooperation.

The Pentagon has said there are about 300,000 British troops in Afghanistan, of whom about 250,000 are in Iraq.

On Tuesday, Defence Minister Michael Fallon made the first public comments about Britain’s plans to withdraw troops from Iraq.

He said the decision on Britain’s future in Afghanistan would be taken by the end in 2020.

“It’s the UK’s decision to make,” he told the House defence committee.

Britain has been a staunch ally of the U