Mouthwash can eradicate coronavirus within 30 seconds of being exposed to it in a laboratory, a startling new scientific study has found.

The preliminary result comes ahead of a clinical trial into whether using over-the-counter mouthwash has the potential to reduce the levels of Covid-19 in a patient's saliva.

It comes months after Donald Trump was lambasted by the medical community after suggesting research into whether coronavirus might be treated by injecting disinfectant into the body.

But research by Cardiff University suggests the outgoing President might not have been too wide of the mark after all after researchers now claim that mouthwashes containing at least 0.07% cetypyridinium chloride (CPC) showed "promising signs" of being able to combat the virus.

The report - The Virucidal Efficacy of Oral Rinse Components Against SARS-CoV-2 In Vitro - is yet to be peer reviewed but supports another study published last week that found CPC-based mouthwashes are effective in reducing Covid's viral load.

The latest test was carried out by scientists at the university's laboratory and mimicked the conditions of a person's naso/oropharynx passage using mouthwash brands including Dentyl.

A clinical trial will next examine how effective mouthwash is in reducing the viral load in the saliva of Covid-19 patients at the University Hospital of Wales in Cardiff, with its results due to be published in the first part of 2021.

Dentyl is the only UK mouthwash brand to take part in the 12-week clinical trial, which is led by Professor David Thomas from Cardiff University and titled: "The measurement of mouthwash anti-viral activity against Covid-19".

Dr Thomas told the PA news agency: "Although this in-vitro study is very encouraging and is a positive step, more clinical research is now clearly needed.

"We need to understand if the effect of over-the-counter mouthwashes on the Covid-19 virus achieved in the laboratory can be reproduced in patients, and we look forward to completing our clinical trial in early 2021."

Dr Nick Claydon, a specialist periodontologist, said he believed the research was "very valuable".

He said: "If these positive results are reflected in Cardiff University's clinical trial, CPC-based mouthwashes such as Dentyl used in the in-vitro study could become an important addition to people's routine, together with hand washing, physical distancing and wearing masks, both now and in the future."