An emergency appeal was launched in November

In October blood supplies reached their lowest level for more than four years.

About 3,000 regular donors who answered the appeal to bring their donation forward will be unable to give blood again until the New Year.

The Scottish National Blood Transfusion Service (SNBTS) has urged new donors to come forward to ensure that the blood supply is maintained over Christmas.

Less than 6% of the Scottish population are blood donors. 6,000 blood components donations (units of blood) are issued every week in Scotland. SNBTS must collect 1,000 units of blood every single day. Anyone between the ages of 17-60 who is generally fit and well can give blood.

It said the response to the October appeal was "tremendous".

However, 12 weeks must be left between donations meaning that it needs to recruit 3,000 new donors.

The SNBTS said that many people were too busy with Christmas shopping and parties to give blood.

Moira Eadie, Glasgow donor services manager, said: "This can cause real difficulties in maintaining supplies for Scottish hospitals and we are obviously very concerned.

"We urge everyone to act now."

The SNBTS said that blood cannot be stockpiled and there is no substitute to support most operations.

The most common use of transfused blood is for premature babies who may require up to 50 transfusions.

Constantly replenished

They are also commonly transfused with platelets, to help blood clot and prevent bleeding.

Platelets last only five days meaning the supply must be constantly replenished over the festive period.

About 200 babies required life-saving blood transfusion treatment in Scotland last year.

Many other patients also rely on blood transfusions.