Blood donors are being urged to keep their appointments before Christmas to avoid stocks becoming depleted over the critical festive period.

Around one in four appointments to give blood were cancelled at short notice by donors in the week before Christmas last year, while one in 10 simply failed to turn up.

NHS Blood and Transplant said it needs people to keep their appointments to avoid an even more serious pre-Christmas slump.

Donors who have reason to cancel are being asked to give at least three days’ notice so the slot can be given to someone else.

It warned a serious drop in donations could affect the supply of blood to the tens of thousands of people in England who will need transfusions over the festive period as treatment for a blood condition or cancer, or due to surgery, childbirth or an accident.

Henry Alderson, two, suffers from the rare condition Diamond Blackfan Anaemia and will need blood over the festive period.

The rare bone marrow failure disorder means he cannot make his own red blood cells and needs transfusions every four weeks to keep him alive.

Henry, from Essex, who turns three this week, has had around 40 transfusions since first receiving blood just minutes after he was born.

His mother Zoe described the transfusions as “supercharging” and said they give the youngster a normal life.

She said: “Henry is a cheeky chappie, always on the go, but in the days before his transfusion he turns as pale as a ghost and his energy levels plummet.

“He is now so used to transfusions that he gets excited about going to hospital and happily watches the needle go in. Once the blood works its magic he is full of energy once more.

“Henry’s best chance at a long and healthy life is a bone marrow transplant, but for now we rely on blood donors to keep him alive.

“His transfusions in November and December will mean he can enjoy Christmas. We are incredibly grateful to everyone who gives blood.”

Mike Stredder, director of blood donation for NHS Blood and Transplant, said: “Demand for lifesaving blood doesn’t stop for Christmas. But stock levels can drop dramatically if too many donor appointments go missed or unfilled.

“We need our loyal donors more than ever at this time of year to make sure hospitals have the blood that seriously ill children and adults will need over Christmas and the new year. Each donation can save up to three lives.”

Existing blood donors are being prioritised for appointments in the run-up to and over Christmas.

New donors who have registered but not yet donated are being asked to make an appointment for the new year.