A thank you note from a thoughtful son to his mum for a surprise present she had bought him has become incredibly precious.

Heartbroken Debbie Adlam holds the piece of paper close as it's words mean everything to her.

At her son PC Andrew Harper's funeral last year Debbie held on to it to keep her boy close, reports Mirror Online.

Andrew was the victim of a callous gang of thieves and his death sickened Britain.

Now the words he wrote as a child in gratitude for a phone she bought him help her through the long days and nights without him.

"This piece of paper has become really special to me," said Debbie.

"Because in my darkest hours I know he will always love me."

In the note, her late son wrote: "Thank you mum, you’re my mate. Thank you for my phone times infinity and for everything you do. Just remember I will love you forever, no matter what."

Today, in a moving interview almost a year on from 28-year-old Andrew’s senseless killing, Debbie, 53, tells how she is still tortured by thoughts of his final moments as he was dragged more than a mile to his death along a country lane by a getaway car, his ankles caught in a trailing strap as he tried to stop three thugs stealing a quad bike.

Debbie Adlam
Heartbroken Debbie Adlam finds an old thank you note from her son PR Andrew Harper helps her get through the pain of his loss

She reveals she makes regular pilgrimages to the road where he died – because it helps her feel close to him.

She speaks of her anger at the sentences handed down to his killers – Henry Long, 19, and 18-year-olds Jessie Cole and Albert Bowers.

And at the sickening sight of them cheering when acquitted of murder after she was told any emotion would see her led from court.

Now Debbie is pouring her grief and fury into a campaign for tougher sentences for police killers – calling for a minimum 20 years in jail with no early release.

It comes after ringleader Long got just 16 years for Andrew’s manslaughter last month.

Andrew Harper
The note has helped her through the long days and nights without him

Cole and Bowers each got 13. They were reduced from the maximum due to their ages and Long’s guilty plea. All will be eligible for release after two-thirds of their sentences in a case that sparked an outcry.

Debbie, who hopes to meet Home Secretary Priti Patel about her crusade next week, said: "They celebrated when they got manslaughter instead. It looked like they’d scored the winner in the FA Cup Final – cheering and hugging each other."

Not a glimmer of remorse. Yet we were warned we couldn’t show any emotion during the case or we’d be told to leave. We had to listen to the devastating detail of what happened to Andrew and we couldn’t react.

"If we cried, we cried silently, because if we’d been visibly upset it could have been used by their defence to undermine the prosecution case.

"What are other criminals going to think when they see that? There’s nothing to put them off. No deterrent. There will be another case like Andrew’s. It’s just a matter of when."

Debbie recalls the day her world collapsed last August, and how their son’s violent death – just four weeks after his wedding to childhood sweetheart Lissie – haunts her day and night.

Debbie is campaigning for tougher sentences for police killers

She said: "Two police officers came to our door and we knew instantly something was wrong.

"You want to refuse to hear what they’re saying. My emotions were in no man’s land."

At first, she assumed her son had died in a car accident – then the horror of what happened gradually unfolded. A pathologist said Andrew was likely to have suffered a massive brain injury as soon as he collided with the road – and probably would have lost consciousness instantly.

But Debbie is consumed by fear that her son was awake.

She said: "I wanted to know everything, but the injuries were worse than I could have ever imagined. No one can tell me 100% that he knew nothing about it and I’ve always had nagging doubts."