Gonorrhoea really can be spread by kissing, leading scientists now claim. 

For decades, sexual health experts have insisted 'the clap' couldn't spread through snogging, and is instead transmitted through unprotected sex.

But researchers say the evidence is now clear enough that the guidance should be changed.

Professor Eric Chow, of the  Sexual Health Centre, told MailOnline: 'We think it is possible to catch gonorrhoea via kissing. 

'I think the guidelines should be updated.'

Gonorrhoea can be spread by kissing, scientists say, as they call for guidance to be changed

In January, his team of researchers conducted a review of six studies that looked at whether tongue kissing was a risk factor for gonorrhoea and chlamydia.

The review, published in the journal Sexually Transmitted Diseases, ruled snogging did raise the risk of becoming infected. 

However, this was not the case for chlamydia. 

Meanwhile, a study published in July, by many of the same researchers, pornaphoto.com determined that kissing could spread gonorrhoea.

It analysed the sexual history and STI records of more than 2,000 gay and bisexual men.

'We found oropharyngeal gonorrhoea was associated with exposure to a partner's mouth through kissing,' the study authors wrote in eClinicalMedicine.