MORE than 4,000 Marines in Afghanistan have been left disappointed after thinking they were getting a big rise in their allowances.

The way that long-term separation allowance was paid was changed this month as part of reforms.

But, because of a blunder by administrators, up to 4,260 Marines were led to believe they were getting a £3,000 bonus.

The Defence Ministry has since realised the error and is saying that the Marines will not get the extra money.

A ministry spokes- woman said the change to the way the allowance was paid aimed to make it simpler to pay.

She said: "The Royal Navy and Royal Marine personnel will be paid under joint Personnel Agency arrangements from this month.

"Regrettably, the internal instruction was wrong and some personnel are disappointed they will not receive this substantial uplift.

"But it is important to note that they are not taking a cut."

The Marines were told they could receive up to £17 extra a day over a six-month period.

Opposition MPs say the mistake will lead to a drop in troop morale.