UK to tighten Afghan police vetting after attack

* Attack leads to renewed questioning of British mission

* Ashdown says government fails to make case for war

* Brown to defend his policy in speech on Friday



By Adrian Croft

LONDON, Nov 5 (Reuters) - Britain said on Thursday it was working to tighten up vetting of Afghan police recruits after a policeman shot dead five British soldiers, but the government faced growing calls to bring its 9,000 troops home.

Prime Minister Gordon Brown scheduled a speech for Friday to defend his policy on Afghanistan in the face of mounting casualties and questioning of Britain's military role.

"We are looking to do all we can to improve vetting," Armed Forces Minister Bill Rammell told the BBC in the wake of Tuesday's attack, in which the policeman escaped.

All new recruits to the Afghan police already had to have a character reference from a senior police officer or community leader saying they did not have links to Taliban insurgents, Rammell said. Recruits were tested for drug use.

But, highlighting the limitations of vetting, he said there were few, if any, criminal convictions in Afghanistan.

Brown's spokesman said Britain had been working with Afghan police commanders to improve recruitment and vetting procedures.

"Clearly we need to look at that again," he said.

The Taliban claimed responsibility for Tuesday's attack when the British soldiers were killed at a military compound in Helmand province in southern Afghanistan.

The rising losses in Afghanistan, where 229 British soldiers have now died, pose a problem for Brown, whose party lags in opinion polls with an election no more than seven months away.



BLOW TO BROWN'S STRATEGY

The latest attack struck a blow at Brown's strategy, which calls for speeding up training of the Afghan army and police so they can take over security duties from foreign forces.

Paul Flynn, a member of parliament for Brown's Labour Party, said British politicians were "deluded" about the mission.

"We cannot succeed in Afghanistan and we must stop now sending our young men out there to die in vain," he said.

Britain was relying on an Afghan police force that was "endemically corrupt", he told the BBC.

Paddy Ashdown, former U.N. representative for Bosnia and once tipped for a similar job in Afghanistan, said the government had "completely failed both to make a cogent case for this war or to convince us that it has a strategy worthy of the sacrifices being made.

"There is a real chance we will lose this struggle in the bars and front rooms of Britain before we lose it in the deserts and mountains of Afghanistan," he wrote in The Times.

Former Foreign Office minister Kim Howells said this week Britain should withdraw most of its troops and focus on security at home.

Brown says British troops are needed in Afghanistan to protect Britain against terrorism at home. He regularly says three-quarters of terrorist plots in Britain have been hatched in the mountainous areas of Pakistan or Afghanistan.

U.S. President Barack Obama is due to decide within weeks whether to approve a request from his commander in Afghanistan for tens of thousands of additional troops.

Brown has pledged to send 500 more British troops to Afghanistan, provided certain conditions are met. (Editing by Mark Trevelyan)