Erectile dysfunction – or impotence – is the inability to get and maintain an erection, according to the NHS.
One in ten men worldwide are thought to suffer from the condition.
New research has revealed the area of the UK where most men have it.
London tops the list with 40 per cent of men having suffered, while Wales was shown to have the least at 12 per cent.
Causes of erectile dysfunction can include high blood pressure, diabetes, hormonal problem, anxiety and depression.
The findings by Pharmacyoutlet.co.uk were part of a nationwide survey into Britain’s most embarrassing illnesses that involved 2,000 people.
These included sexually transmitted diseases (STDs), bad breath, acne, irritable bowel syndrome (IBS), athlete’s foot, snoring and worms.
London once again fared worst when it came to snoring – with 42 per cent suffering – as well as athlete’s foot, worms, acne, IBS, bad breath and STDs.
However, people from Northern Ireland were found to have the highest levels of incontinence – or a weak bladder – and constipation or diarrhoea.
Worryingly, 78 per cent of those asked had experienced the latter.
In contrast, the north east was found to have the fewest people who had suffered from STDs at four per cent, and constipation and diarrhoea at 57 per cent.
The west midlands came bottom of the list for acne and athlete’s foot, while the south east had the lowest levels of bad breath.
“Today’s research reveals just how commonplace many illnesses – some of which can be the source of some embarrassment – are across the UK,” said Hitesh Dodhia, superintendent pharmacist at PharmacyOutlet.co.uk.
“In particular, it shows that those in the capital are often the most at risk when it comes to contracting some of these ailments.
“It is of vital importance that anyone who develops unwelcome symptoms seeks the necessary medication and professional support.
“Do not suffer in silence through fear or embarrassment – many of these problems are extremely common and can be resolved through a visit to a pharmacist, GP or doctor.”