The message from the Scottish National Blood Transfusion Service (SNBTS) at the launch of its latest campaign is that just three teaspoons of blood could save a premature baby's life.

At the Glasgow launch, on Monday, the SNBTS said the summer months are always "worrying" because donations tend to fall by as much as 10% from now until September.

Spokeswoman Moira Carter said: "Donors are away or rushing around preparing for holidays, but the demand for blood never goes away and it can not be frozen or stockpiled."

A little less than one pint of blood is taken in a donation

But she said it is important for people to realise the potential value of even just a small amount of donated blood.

Ms Carter said: "With almost 50,000 live births every year, we need a huge amount of blood just to make sure babies and their mothers are safe.

"We want everyone to understand that as little as two units of blood can mean a lot to a recipient."

Ms Carter said the service was troubled by the fact that 94% of the population do not give blood.

There are 10,000 Caesarean sections every year in Scotland and 100,000 donations are needed to safeguard every birth north of the border annually.

The SNBTS also said that in 1991, people aged 17-24 accounted for 26% of the donor base, but just 20% of the base now.