O Rh negative (0-) and B Rh (B-) are urged to come forward before Christmas and before bad weather sets in.

The NHS has issued an urgent appeal for blood donations in the run-up to Christmas. It fears bad weather could set in at a time when donations traditionally dip and wants to boost stocks now.

The appeal is aimed at O Rh negative (O-) and B Rh negative (B-) blood donors.

Jon Latham, of NHs Blood and Transplant, said: “Blood donors from every blood group are needed every day.

“However, we are taking a range of additional measures including radio advertising and targeted marketing, to encourage more O Rh negative and B Rh negative donors to book appointments to give blood before Christmas.

“If more donors can spare the time to give blood in December this will give blood stocks a timely lift in the run up to Christmas and allow them to be maintained at a constant level as January approaches.

“We would like to reassure everyone that blood stocks are not low and patient care has not been affected in any way.”

Donors with blood group O Rh negative are typically known as the “universal donor” as their blood can be given to patients with a different blood group. This can prove vital in an emergency situation when there may not be time for an immediate blood grouping test to be carried out. Approximately seven per cent of the population have this blood group.

Donors with the blood group B Rh negative are more often found in Black and Minority Ethnic (BME) communities. Only two per cent of the population have this blood group and more donors of a BME origin are particularly needed.

To be potentially eligible to give blood you must be aged between 17 - 65, weigh over 7st 12lbs (50kg) and be in general good health.

There is no upper age limit for blood donation if you have donated in the last two years. To find out more about becoming a blood donor or to book an appointment please call the Donor Line on 0300 123 23 23 or log on to www.blood.co.uk