A Birmingham teacher who has shed over six stone has revealed how running has "probably saved his life" as he prepares for his biggest challenge yet.

Stuart Warner, who teaches English at Colmers Secondary School in Longbridge, would not have even dreamt of entering the Simplyhealth Great Birmingham Run half marathon when he tipped the scales at over 25st almost two years ago.

But the 33 year old, who says running has been central to his weight loss, is taking on the annual 13.1-mile challenge around the city's streets on Sunday October 15.

Enter the Great Birmingham Run here

Stuart amazed himself by completing his first-ever running event, the Simplyhealth Great Birmingham 10k in April, and now weighs 19st 3lbs, having shed ten inches from his waist over 21 months.

Most importantly of all, he believes taking up running will help to prolong his life.

English teacher Stuart Warner is tackling the Great Birmingham Run 2017 after losing six stone. Pictured here before losing the weight
English teacher Stuart Warner is tackling the Great Birmingham Run 2017 after losing six stone. Pictured here before losing the weight

Edgbaston resident Stuart said: "I wasn't concerned that I was about to die when I was over 25 stone.

"But I knew if I didn't change my ways, I would have died sooner.

"Whenever I checked my blood pressure, everything looked normal but, ultimately, staying at that weight could have had a big effect on my health in the future."

Stuart plans to watch the inaugural and sold out Birmingham International Marathon, which starts on the morning of October 15, outside his home before heading into the city for his event - the UK's second largest half marathon - early afternoon.

He started running after watching last year's London Marathon on TV, then checking out the Get Inspired section of the BBC website and following the 'couch to 5k' app.

Download a Great Birmingham Run training plan here

He added: "I was taken aback by all the amazing runners on TV but soon realised they hadn't always been amazing - they were ordinary people who must have started somewhere.

"After my first run, I thought I was going to die. However, my work colleagues were really supportive and the couch to 5k app was brilliant.

"It was all about marginal gains and just eight weeks later I went out and did a 5k run. I know it sounds twee but those eight weeks changed my life. In fact, they've probably saved my life.

Stuart Warner is in full training for the Great Birmingham Run 2017
Stuart Warner is in full training for the Great Birmingham Run 2017

"The half marathon is without doubt my biggest challenge yet but so was the 10k and I achieved that. I'm excited for it and will achieve it."

He admits his time at university contributed to his huge weight gain, saying: "Moving away from home, having access to catered halls, a fry up every morning, big dinner every night, eating and drinking what you want.

"Before long, you end up weighing whatever stone. Every time I tried to lose weight before, I did well to start with but it's about sustaining it and keeping it off."

He is raising money for the Alzheimer's Society as his father Derek, 77, was diagnosed with the disease in 2012.

A weekend of running in Birmingham kicks off on Saturday October 14 when children aged three to 16 take part in the Simplyhealth Junior and Mini Great Birmingham Run at Alexander Stadium.

All finishers will receive a goody bag and medal - sign up here.

How to enter the Great Birmingham Run

You can still enter the half marathon which takes in city sights such as Selfridges, Cannon Hill Park, Edgbaston Stadium and Bournville.

Those who sign up for this year's Great Birmingham Run are offered an exclusive entry window for the Birmingham International Marathon 2018 - to enter visit here.

Anyone who entered the Great Birmingham 10k in April will receive a £10 discount for the Great Birmingham Run.