When you've found your hotel room and parked your suitcase in the corner it's time for brew.

Not when you realise that guests before you may have been boiling their dirty underpants in the KETTLE.

Apparently this antisocial act is becoming more commonplace among travellers, scientists have warned.

Microbiologist Dr Heather Hendrickson, from the Institute of Natural and Mathematical Sciences, in New Zealand, warned that this deeply inconsiderate practice was prone to making guests, who use the kettle for its intended purpose, ill.

Boiling water does not kill all bacteria, certainly not within the few seconds that the water within a kettle reaches 100°C.

A petri dish containing bacteria

And some bacteria and pathogens can survive at temperatures of up to 120°C for long periods of time, according to Dr Hendrickson.

One such pathogen is clostidium botulinum which causes botulism, a potentially fatal disease.

She told the Liverpool Echo : "People are unlikely to have a large number of highly heat resistant pathogens in their dirty undergarments but we do not know what they do have in there or how sick they might be.

“There are simply too many unknowns and hotel kettles are not industrial strength cleaning facilities. Be respectful of other people and don’t do this.

“Boil the water and pour it into the sink for washing items. Don’t put your dirty underwear into the kettle.”