The MoD said it expected the highest standards of behaviour from troops
The head of the armed forces has defended the conduct of British troops abroad after claims that soldiers sexually abused an Iraqi boy.
Air Chief Marshal Jock Stirrup told the BBC that "virtually all" of the "tens and tens of thousands" posted overseas had behaved "impeccably".
He conceded that this "has not been universally the case".
The Ministry of Defence has confirmed that the Royal Military Police is investigating the allegation of abuse.
The alleged sexual assault of a 14-year-old boy is said to have taken place at Camp Bread Basket in Basra, southern Iraq, in May 2003.
"This allegation has been referred to the Royal Military Police for investigation," an MoD spokesman said.
He said all claims of abuse are "investigated thoroughly and where proven those responsible are punished".
The teenager, now 19, claims he was attacked at a British base near Basra in 2003.
Mazin Younis, from the pressure group, The Iraqi League, examines allegations of abuse against Iraqi citizens by British troops.
Mr Younis told the BBC News Channel about the claims made by the boy.
He said: "They were surrounded by British troops... They were beaten, very harshly, using vehicle aerials.
"And they were guided inside the compound, where they were subjected to some horrific types of abuse. And there was continuous beating.
"But the worst of it was the sexual humiliation, which is something new, very new, to Iraqis - considering that they were probably used to or heard of the brutality of Saddam's regime - but this is something they have never experienced before."
The alleged abuse comes just days after it was announced that the MoD would pay nearly £3m to Iraqis who were tortured by British troops in Basra in 2003.
Among those receiving compensation are the family of 26-year-old Baha Mousa who was beaten to death in custody.
On the wider issue of abuse allegations, Sir Jock, the chief of defence staff, told BBC One's Andrew Marr Show: "We have had tens and tens of thousands of military people going through operational theatres, operating in the most dangerous and most difficult and most stressful conditions, and virtually all of them have behaved impeccably.
"When it is not the case, we are first amongst those who want to see it dealt with because we cannot accept people failing to live up to the high standards that we set."
But he was keen to stress that any ongoing abuse allegations were subject to proper police investigations and "we need to see what they come up with".
Mr Mousa died while in the custody of the former Queen's Lancashire Regiment.
The MoD said: "The Army has done a great deal since cases of abuse related to the death of Baha Mousa in 2003.
"Procedures and training have been improved. But we are not complacent and continue to demand the very highest standards of conduct from all our troops."
No regiment has yet been named in connection with the latest allegation.
According to the Independent on Sunday newspaper, the boy, now aged 19, is launching a civil case against the MoD.