Because she is a brave, intelligent and kind-hearted woman, my friend Angela (not her real name) sometimes volunteers to work in the local night shelter for homeless people.

But Angela is a qualified first-aider, which makes her evenings there much more eventful. Over Christmas, she and her husband went to the shelter together. He sat in the common room and played board games with some of the visitors; Angela was chatting to someone at the front door when a shout was heard: “First aid! My mate’s been hurt!”

Angela ran over to find out what was happening. A man told her: “My mate’s fallen over in the toilets. He’s cut himself, there’s blood everywhere.”

Angela pushed open the toilet door. A man lay face down on the floor, which was sticky with blood. It was hard to see because of the blue-tinted lighting, put there to stop drug addicts using the toilet as a place to inject themselves. Lighting aside, the injured man was clearly under the influence of some sort of drug. Getting closer to him, Angela saw that his pupils were tiny, like pinpricks. He wasn’t breathing, but his pulse was racing faster than any she’d ever felt before.

She had to kneel down in the sticky bloody mess and resuscitate him. She asked the first man - the one who’d said his mate had fallen over - what the injured man’s name was. She got a blank expression in reply, then: “Danny. He’s called Danny.”

Angela worked with Danny, trying to get a response. She held his hand, saying: “Danny, if you can hear me, squeeze my hand. Danny? Danny? Are you with us Danny?” Nothing.

Despite the dim light, Angela saw what had happened. Danny fell chin-first to the floor, probably unconscious, and punctured his lower lip with his teeth. There was a wide gash opening up an obscene extra mouth underneath his existing one. That’s where all the blood was coming from. She closed the wound as best as she could and tried to dress it, and gradually the bleeding slowed down.

Finally, just as the ambulance crew arrived, Danny’s hand gave the tiniest of squeezes. She cried out: “You can hear me! You’re going to be alright, Danny. There’s an ambulance here, we’re going to get you into hospital.”

The paramedics worked around him and slowly, Danny came round. He blinked. He looked at Angela, still holding his hand.

“Who’s Danny?” he asked, his voice cracked by his splintered lip.

“You are, aren’t you?” replied Angela.

“My name’s Dave,” he said. “I could hear you going on about Danny, but I thought maybe you were talking to someone else.”

They picked him up on a trolley and took him away. Angela - a woman I cannot fail to respect enormously when she tells stories like this - got up from the pool of blood she’d been sitting in, and went to find her husband. He was still playing board games.