CELTIC and Scotland legend Danny McGrain may be one of football's "nice guys" but he admits sometimes he is almost tempted to violence.

The defender, once rated as the world's best in his position, beat diabetes to have a successful 20-year playing career and still stays fit as he trains the reserves at Parkhead.

But when he sees people neglecting themselves in a way that could trigger their own battle with diabetes, he confesses he gets frustrated.

He is not surprised Scotland faces an "epidemic" of the condition that can be inherited, as in his case, or develop later in life, often as a result of obesity.

It is estimated that if trends continue 371,000 Scots could be living with diabetes by 2025, as eating and exercise habits put them at risk. Yesterday it emerged the number of people diagnosed with Type 2 diabetes has jumped by 18% in five years.

Obesity is a key factor in Type 2 diabetes but smoking, lack of exercise, poor diet and excessive alcohol are also factors.

Tired Colin diagnosed his illness With a decent diet and a lifetime playing sport that stretched well into his 40s, Colin Campbell could never have imagined he was one of the 60,000 Scots living with unknown diabetes. But when he started to feel symptoms that could be caused by the illness, he was not left in doubt for long - he diagnosed himself. The senior lab technician at Glasgow University, 58, began to worry about three years ago when he found he had no energy. He was also constantly thirsty and going to the toilet frequently. Mr Campbell, who lives in Cumbernauld, said: "In my first job, one of the things I did was to conduct the conclusive tests for diabetes so I knew of the condition. "We have the equipment here so I ran a test for myself. When that was positive I went to see my GP for confirmation. It finally made sense of my symptoms." His doctor prescribed two sets of tablets to help him control his blood sugar level. Unlike people in the highest risk groups, Mr Campbell is not obese, but he admits his weight is "at the top of normal" and he is a little heavier than he would like to be. He has the Type 2 form so he can control it with tablets, sensible exercise and a healthy diet. Mr Campbell now has a daily rota of walks in Kelvingrove Park, which is near the university, and evening strolls with his wife. He said: "It is not making much of a difference to my life just now, but I know it is a progressive condition. I have had to increase the dose of one of my tablets to control my blood sugar."

And it makes Danny angry to see people risking heart attacks and blindness, some of the complications associated with diabetes, because of poor decisions.

He said: "Eating pies and chips all the time and drinking a lot of beer is a choice. But far too many young people are getting diabetes and we need to change that.

"Sometimes you wish you could slap them in the face and say, Don't do this'. You know what the outcome is going to be, you'll turn into a slob."

The defender captained both Celtic and Scotland in a career that began as a 17-year-old in 1967. But at the age of 24, at the World Cup finals, he was found to be ill and Type 1 diabetes was diagnosed on his return home.

His body was not producing enough insulin and his blood sugar was hitting danger levels.

He said: "I had been lethargic. I had this terrible thirst and at the same time I was up and down to the toilet during the night.

"I went out to the World Cup weighing 11st 4lbs and came back 9st!

"I inherited diabetes. It turned out my uncle had it but I didn't know. Back then people kept it to themselves."

While he had to tell club manager Jock Stein why he had been in hospital, he kept news of the illness from other players.

He said: "I didn't want to be a flagbearer for diabetes and then find six months later it had stopped me playing."

That worry has long gone and he still plays fundraising matches for Football Aid, which gives thousands each year to groups battling the potentially fatal disease.

Danny said: "I'm fit for a 58-year-old. I played 90 minutes for Football Aid this year and so did Neil Lennon. He was happy to get involved."

260,000 Scots are victims

Being overweight, particularly very overweight or obese, brings the highest risks of developing diabetes in later life.

Just under 200,000 people in Scotland are known to have the condition, but a further 60,000 are believed to have it without knowing.

This puts them in real danger of complications because they cannot control their condition and the damage it causes.

Last year almost 1850 Scots were admitted to casualty units fighting for their lives after suffering Ketoacidosis, a major complication from diabetes.

Ketoacidosis is caused by extremely high levels of glucose in the blood and a severe lack of insulin. This, in turn, leads to the body trying to break down fat for energy, resulting in a build-up of dangerous chemicals that is always fatal if left untreated.

Type 1 diabetes is often diagnosed by late teens and patients must inject insulin.

Type 2, sometimes called late onset diabetes, is where patients' bodies no longer respond to the insulin they produce. It can usually be regulated by pills.

This week it emerged the children of women who ate a lot of junk food during pregnancy were more likely to develop obesity and diabetes in later life.

Doctor Stephanie Bayol said: "A mother's diet while pregnant and breastfeeding is very important for the long term health of her child."

While clubs like Celtic have dieticians and doctors to help keep players in good shape, Danny McGrain insists less sporty types can look after themselves just as well.

Moderate exercise, such as walking or swimming, and a healthy balanced diet - with five portions of fruit and veg a day as well, as avoiding high-fat sugary foods - will help cut the risk of diabetes.

Danny said: "Thinking about what you eat is about being a healthy human being. If you don't pay attention and get Type 2 diabetes, you will be forced to make drastic changes to your lifestyle.

"You have to choose if you want the pies and chips and beers or you want to live."

For how to cut the risks see: www.diabetes.org.uk.