• Video report by ITV News Science Editor Tom Clarke

Bridget Barker stopped smoking 15 years ago, but when she was invited by her GP to take part in Europe's largest lung cancer screening study, shejumped at the chance.

And the 77-year-old's willingness to take part in the project paid off after her scan revealed very early signs of lung cancer.

The cancer was detected early enough for Bridget to be cured without having to undergo extensive and invasive treatment.

"When they came round to tell me I wouldn't need to have any chemo orradiotherapy what more could you ask for? It really was like winningthe lottery - and a big lottery," Bridget told ITV News.

Bridget was part of the SUMMIT Trial based in north and east London which is screening 25,000 former or current smokers.

Patients are also given a low dose CT scan of their lungs. Credit: ITV News

As well as a lung health check, patients have a low dose CT scan oftheir lungs. The objective is to see if targeted screening is a costeffective way of fighting Britain's deadliest cancer.

"The 25,000 people we hope to scan; we should detect about 600 to 800lung cancers, the majority of which will be very early stage," Prof Sam Janes from University College London Hospital told ITV News."And those people will be sent on to the hospital very quickly andhopefully have curative treatment such as surgery or radiotherapy."

The NHS study it is being funded by a US company investigating a blood test for cancer.

Tests like these are several years away but as they are quick and easy, they could transform cancer survival.

Testing for cancer could transform cancer survival rates. Credit: ITV News

In a separate trial, NHS England has begun lung health checks in 10 areas across the country that is aiming to screen up as many as 600,000 smokers or former smokers between the ages of 55 and 74.

Checks should detect around three and a half thousand cancers early, potentially saving hundreds of lives a year.

Bridget Barker's cancer would almost certainly have killed her and she urges others to take up the chance of taking part in these studies if they are offered it.

"Everybody who's an ex-smoker, it doesn't take long and 99% of people will be fine."