The new donor centre in Glasgow has been busy

The Scottish National Blood Transfusion Service (SNBTS) is appealing for new donors in a bid to avert the crisis.

It said reserve stocks were so depleted that planned operations may have to be cancelled within two weeks.

Dr Moira Carter, of the SNBTS, said: "There are not enough blood donors to support Scottish health care."

The service has been forced to appeal for new blood donors for the first time in four years.

Dr Carter, the national donor services manager, said: "We urgently require new donors to come forward within the next month.

"We always experience a significant drop in donations during the summer period because of holidays, but this year, despite our best efforts, supplies have not recovered and are now at a seriously low level."

Go and do it, it's no big deal, honestly. I don't like needles but that doesn't frighten me Irene Devlin

Reserve stocks have become depleted after the service received 7,500 fewer donations than expected.

Supplies of blood matched to the patient must be available for every birth, operation and accident and emergency case.

Those suffering a serious illness can use up to 100 units of blood during their treatment.

However, fewer than 6% of the Scottish population are blood donors.

The service said it needs to find at least 120 new donors each day to meet demand and rebuild supplies over the next four weeks.

Dr Carter added: "The situation is very serious. I urge all Scots to come forward and give blood as a matter of priority."

SCOTLAND'S BLOOD SHORTAGE Blood donors explain why they are responding to the appeal In pictures

That message was echoed by Tory health spokesman David Davidson.

"This is worrying news that our blood transfusion service is running dangerously low in supply," he said.

"But I am sure that the Scottish people will respond to avert the problems that could arise if operations are cancelled."

Queues at centre

However, the Blood Transfusion Service in Glasgow reported a good response to its appeal on Tuesday morning, from both first time and regular donors.

Queues had formed by 0920 BST, even thought the donation centre did not open for business until 1100 BST.

Getting the message across in Glasgow

Irene Devlin last gave about five years ago and said she felt guilty when she heard about the shortage on Tuesday morning.

"I didn't stop on purpose, twice I'd been before I wasn't allowed to give because I had a cold sore then the second time was the blood level was too low to donate so after that I got out of the routine.

"I did feel bad because I had done it before and there's nothing to it, nothing to it all.

"Go and do it, it's no big deal, honestly. I don't like needles but that doesn't frighten me - nobody likes needles. and the blood comes back into your system within 24 hours.

"I feel fine. It's no big deal.