The stepfather of a soldier badly wounded in an attack on a Taliban fortress said he was shocked by the revelations that troops could have been exposed to contaminated blood.

The Ministry of Defence has announced that 18 soldiers, seriously injured in Iraq and Afghanistan, were given transfusions which could be contaminated with infections such as HIV, hepatitis or syphilis.

Andy Webster, stepfather of Royal Marine Steven Spiwak, of Denholme, whose foot was shattered in the assault last January, said he was shocked by the revelations.

Steven, 22, is now back with his unit, 45 Commando, in Arbroath, and awaiting reconstructive surgery.

"It's rough on the troops if this blood is not checked properly," said Mr Webster.

"It's bad enough having to go out there and get shot at without having to face the fear of getting HIV."

He said they were not fearful that Steven was involved because he had his treatment in the UK about a year ago.

Steven's mother, Janice Webster, said the family was particularly concerned about the outcome of his reconstructive surgery.

The operation would involve removing a piece of bone from his thigh to be used in his foot, she understands.

"We were very happy with his initial treatment but Steven is concerned about the next operation," she said.

"It is frustrating for him because he will be disabled again for a while until he recovers and until then won't know if he will be able to continue in the Royal Marines.

"It could affect his career and he definitely wants to continue."

The 18 transfusion victims are understood to have been treated in American medical centres.

Defence Minister Derek Twigg said procedures were not followed in terms of retrospective testing by the Americans.

Although the risk of infection was low, he stressed the matter was being taken very seriously.

"As soon as we had confirmation of the names, we started the process of informing people and their GPs and medical officers," he said.

All the UK service personnel whose transfusions might not have been valid, were being contacted.

But any member of the forces concerned about a transfusion should contact their own doctor or medical officer.

Steven was among the first troops to charge through a breach in a fortress held by the Taliban.

They were beaten back in a hail of bullets and he was wounded in the right knee and more seriously in his right foot.