As part of Camden Town’s safer neighbourhood team, helping crime victims and sometimes even saving lives is all part of the day job for PC Andrew Harris. But now the kindhearted copper is hoping to save someone’s life in his spare time too – by donating stem cells to help a cancer patient.

The father-of-one was among a group to give a saliva swab when a team from the Anthony Nolan charity visited Holborn police station in 2009.

“A load of my colleagues were stepping forward. I thought, no problem, I can spit into a tube and I didn’t think about it again,” he said.

Until last April, when he was surprised to get an email telling him that he was a perfect match for a patient.

“I had forgotten all about it. At first I thought it was a scam email. But I contacted the charity and realised it was real.

He said: “I then didn’t hesitate. How could I say no? I joined the police force to help people and to have the opportunity to save someone’s life like this is amazing.”

He was inspired by his mother Patricia, who worked as a cancer nurse at the Royal Marsden.

“She is an inspiration and has worked with cancer patients since I was little,” he said.

He admits at first he felt anxious about the procedure: “People kept saying it would be painful and that they would have to drill through my bone to extract cells, but that is a complete myth.

‘‘It is a relatively simple process – no more painful than giving blood.”

PC Harris knows little about the patient he will help, apart from that she is an adult female.

The donation has already had to be put off once when the patient’s condition deteriorated but she is now well enough and it is scheduled to take place on September 30.

PC Harris will have growth hormone injections for five days before, to stimulate blood cell production. Then he will go to University College Hospital and have blood taken.

The blood will be put through a machine and stem cells will be extracted and transplanted to the patient.

“It is as simple as that,” he said.

Anthony Nolan say for nine out of ten donors, that is all that is required. However one out of ten may have to undergo a second procedure which involves a general anaesthetic.

PC Harris, who has a 15-month-old daughter, said: “There needs to be more awareness. It’s such a simple way to be able to give someone hope and to give them a chance.

‘‘I would encourage everyone to do it.”