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.”

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