The MoD says that it is too dangerous and costly to send extra aircraft and will "politely decline" offers from British companies or charities wanting to send Christmas boxes.

But the refusal by the MoD could damage the morale of the 14,000 British troops, according to some critics.

A spokesperson for the MoD told SM: "We have been advised by commanders in Iraq to politely decline offers of gifts from UK companies because of the overwhelming effect [it would have] on the supply chain."

She added that the cost of airlifting items to Iraq would be more than the value of the gifts and put resources under pressure.

"But we are considering offers where we think it is appropriate and there is no limit on gifts that parents and families can send."

During the first Gulf war, extra gifts were sent because there were already scheduled ships with available space, but that was not the situation this time, the spokesperson said.

However, Keith Hartley, professor of economics and director of the Centre for Defence Economics at the University of York, said it was "extremely surprising and worrying" that the MoD could not accept gifts.

"The cost of shipping Christmas gifts out appears trivial when compared with the other costs - those of the war itself and the damage to troop morale," he said. "These troops are going to be there for a long time and will no doubt be envious of American troops receiving gifts."

Each of the 120,000 US military men and women stationed in Iraq will receive gifts including T-shirts, books and video games, according to the US government.

But a spokesman for the Defence Logistics Organisation said the MoD had made the right decision, as military supply chains were operating in a different environment to the first Gulf War in 1991, so the MoD is applying a case-by-case approach this Christmas, he said.

Frank Steer, secretary-general of the Institute of Quality Assurance and a former brigadier in Army Ordnance, said: "Extra gifts are a huge burden and can interfere with the flow of normal mail. When the first Gulf war ended we had around 40 containers of mail left undistributed."

He added that gifts could boost morale, but "the issue is best left to the chain of command and to families".