The father of a soldier sent to help train the Afghan national police has told of his growing fears for his son's safe return.

Steve Hewitt, from Market Harborough, spoke out days after a rogue Afghan policeman turned his gun on British soldiers, killing five and wounding six others.

His son Josh, 23, flew to the war-torn country in October to start a six-month tour with the Coldstream Guards. Josh's duties involve mentoring the Afghan national police.

Today, Mr Hewitt said: "When Josh went out there I couldn't help but think 'Is he going to come home?' This puts more doubt in my mind."

The 49-year-old firefighter and former soldier said when he heard of the deaths of the five soldiers he was filled with anger and sorrow for their families.

He said he is now questioning the Government's decision to stay in Afghanistan.

"When I heard that it was a member of the police force that had carried out the attacks, I could have kicked the TV in," said Mr Hewitt.

"We are out there fighting a war against the Taliban, and now it seems we are fighting against the police as well.

"If we are gong to lose troops in this way then we should look at bringing them out."

Since news of the killings was made public, military figures have said security problems are rife in the Afghan police.

Captain Doug Beattie, who mentored Afghan soldiers and police officers in Helmand in 2006/7, told The Guardian newspaper: "Whether people will admit this openly or not, it is a fact the Afghan police have been infiltrated at every level by the insurgency."

Mr Hewitt said his son had told him he had witnessed fighting between two members of the Afghan national police while on patrol.

Warrant Officer Class 1 Darren Chant, Sergeant Matthew Telford and Guardsman James Major, from the Grenadier Guards, died in the attack, alongside Acting Corporal Steven Boote and Corporal Nicholas Webster-Smith, of the Royal Military Police.

Another six British soldiers and two Afghan policemen were wounded in the shooting – claimed by the Taliban – at a police checkpoint in Nad-e-Ali, in Helmand Province, on Tuesday.

The soldiers had been living and working at the checkpoint as part of a team mentoring Afghan national police officers.

Some reports suggested they had taken off their body armour and were drinking tea with their Afghan colleagues.

The policeman is aid to have opened fire without warning.