In the study, researchers examined 6,739 patients aged 52-79. In total, 9.1% of the participants had diabetes.

However, in 22% of men with diabetes, their condition was previously undiagnosed. For women, only 12% of cases were previously unrecognised.

Simon O'Neill, head of care, information and advocacy at Diabetes UK, pointed out that men are generally worse at looking after their health than women.

‘We already know that middle-aged men are twice as likely to have diabetes than women and that, consistently, more men are overweight than women and so at greater risk of type-2 diabetes,' he said. ‘This research suggests this pattern is the same for men over 50 who don't realise they have diabetes.'

He added: ‘It's vital men of all ages take better care of their health and are made more aware of the risk factors and symptoms of diabetes. Older men, especially if they are at risk of diabetes, should have regular check ups with their GP.

‘Women should not become complacent, either. They may tend to develop type-2 diabetes later in life but the risk of death from heart disease associated with the condition is about 50% greater in women than it is in men.'