A Labrador who sniffs out her diabetic owner’s blood sugar spikes has become a life-saving watchdog.

Dottie is a medical alert assistance dog and lives with 10-year-old Jack Hales who has Type One diabetes.

Jack was diagnosed when he was four and can suffer from hypoglycaemia – where blood glucose drops so low that unconsciousness and fits can occur – or hyperglycaemia, where blood sugar surges too high.

Jack’s family, from Sutton Valence, had to quickly gain a deep understanding of the condition, and mum Heather Mansell, 51, visited Jack’s school (Headcorn Primary) to show teachers how to inject Jack with insulin – which regulates blood sugar.

A breakthrough came when Heather’s nephew mentioned how dogs could detect diseases like cancer and diabetes through subtle changes in body odour.

Heather said: “Jack was frightened of dogs, but still looked into the Medical Detection Dogs (MDD) charity, and wrote to them asking if he could have an alert dog.

“At the time, we could only say to Jack that the charity probably had hundreds of people writing to it. But he received a reply on Christmas Eve 2015 to say he would be getting a dog – the best present ever.”

After MDD matched Dottie with Jack, the family went to meet her in October at the charity’s Milton Keynes base.

Supervised training then took place with charity instructor Lydia Swanson before Dottie joined mum and son, dad Andrew and older brother Tom, 15.

Heather said: “The bond between them is amazing. She literally ‘guards’ him and it is unbelievable what she can do.

“If Jack has a ‘hypo’ in the night she will wake us by pawing the bed. If she gets no response she will jump onto the bed. She always recognises the danger signals – sometimes before Jack does. She really is a lifesaver.

“I never used to sleep properly because I was always worried Jack could be in danger. Now I sleep better as I know Dottie will alert us if something happens.”

Dottie rests while Jack is at school and enjoys everything a normal family dog does – walkies, eating and lots of attention.