More than 50,000 Scots are carrying a faulty gene which puts them at high risk of developing coronary heart disease or sudden death, a charity has warned.

The British Heart Foundation (BHF) said the majority of people affected are undiagnosed and unaware they may be at risk of a deadly heart attack or cardiac arrest.

It said the figure is 18,000 higher than previous estimates due to better understanding of the prevalence of inherited heart conditions.

The figure could be higher still due to underdiagnosis and undiscovered faulty genes.

Inherited heart conditions can affect people of any age and each child of someone with an inherited heart condition can have a 50% chance of inheriting the faulty gene.

For many families, the first sign there is a problem is when someone has a sudden cardiac arrest with no obvious cause or explanation.

Each week in the UK around 12 seemingly healthy people aged 35 or under are victims of sudden cardiac death with no explanation.

BHF-funded research has helped to discover many of the faulty genes that cause inherited heart conditions, which has led to the development of structured genetic testing services for those at highest risk for some of these conditions.

The charity said more research is urgently needed to better detect and treat these conditions to stop the devastation brought to loved ones, who could also be at risk themselves.

Professor Sir Nilesh Samani, BHF's medical director, said: "The reality is that there are thousands of people across Scotland who are unaware that they could be at risk of sudden death.

"If undetected and untreated, inherited heart conditions can be deadly and they continue to devastate families, often by taking away loved ones without warning.

"Thanks to the public's kind support BHF-funded researchers have discovered some of the genes responsible for these frightening conditions but there is still much to do.

"We urgently need to fund more research to better understand these heart conditions, make more discoveries, develop new treatments and save more lives."

The BHF has launched a new television campaign to raise awareness of the sudden devastation caused by heart disease.

In the advert, a bridesmaid suffers a cardiac arrest due to an inherited heart condition on her sister's wedding day.

It will be broadcast on Wednesday night during Midsomer Murders on STV.