The shadow defence secretary has been criticised after accusing fire fighters of "behaving like Saddam's friends" in planning to strike as war with Iraq looms.

After a recent collapse in talks with employers the Fire Brigades Union announced it would begin a 24 hour strike next Thursday.

But that move, at a time when many are predicting that British troops could be engaged in military action in the Middle East, prompted Conservative anger.

Thousands of members of the armed forces will be needed in the UK to cover for the striking fire fighters, undermining moral and damaging effectiveness, said Bernard Jenkin.

He told BBC Radio that the military was "under the most amazing strain" at the moment.

"Don't underestimate the cost to training and morale in the armed forces, and it's adding to the knock-on effects from which the armed forces will take years to recover in terms of what they call the training and readiness cycle. This is degrading the quality of the armed forces," he said.

Jenkin also accused the FBU officials of having in the past been guests of Saddam's regime on visits to fire stations in the country.

"It does look as though the leadership of the Fire Brigades Union are behaving like Saddam's friends," he said.

"I do think this strike looks as though it's timed impeccably to coincide with the hostilities."

Responding to the claims, the FBU warned that they were "potentially defamatory".

"They are also odious and wrong and are insulting to the fire fighters called up as reservists who are currently in the Gulf as well as insulting to the many fire fighters who are ex-service personnel and who served in previous conflicts," said a spokesman.

"Bernard Jenkin is a disgrace to his party and it will remain unelectable as long as it is represented by such appalling politicians.

"If anyone has been friends with Saddam it has been previous government administrations of this country and America who supplied him with the very weapons or potential to build the weapons about which they now complain."

The union later warned that legal advise suggested the comments were "potentially libellous".

"We are demanding a public retraction of these comments and if he will not do that, we will consider further action or demand that Ian Duncan Smith sack him."

As the row over his comments grew, the shadow defence secretary appeared to moderate his comments.

Speaking at the Conservative Spring conference in Harrogate he said that "the Fire Brigades Union are not friends of Saddam Hussein, but they have been behaving like friends of Saddam Hussein and they have laid themselves open to that misinterpretation".