POLICE are urging unsuspecting short-term holiday hosts to be vigilant - as their properties might be being used as brothels.

Officers say there has been a sharp rise in the number of "pop-up brothels" but owners are often left unaware.

The trend sees prostitutes operating from short-term and holiday rental properties instead of a permanent address in a bid to avoid detection.

The properties can be easily booked online and without the need for large deposits or for the tenants to meet with hosts during the stay.

Avon and Somerset Constabulary has now issued a series of signs to watch out for to try and stop the practice.

Superintendent Mark Edgington said: "Pop-up brothels in short-term rental properties are increasingly being reported across the UK and it is important that property hosts are able to recognise the signs of potential modern slavery and sexual exploitation.

"Many hosts are completely unaware their properties could be used for this or the signs they should be looking out for.

"If using an online booking service, we would always suggest that hosts check the profile of anyone requesting to book their property and read the reviews from other hosts.

"This can help people get to know their guests and share any expectations about using the property with their visitors.

"Some online services will also allow hosts to require that all guests provide identification before they are able to book.

"This can give some assurance that the tenant is really who they say they are."

Worringly, the force said almost half of the intelligence reports about human trafficking and modern slavery last month centred on the exploitation of females in off-street prostitution.

Sergeant Emma Slade added: "Vulnerable women are being enslaved and exploited for sex within pop-up brothels, they are isolated and suffer terrible abuse.

"Many of the women are recruited and trafficked on false promises of legitimate work but find themselves in a very different circumstance.

"If hosts are able to assist with identifying premises that may be being used to sell sex, they will be helping to protect those people inside who are often being forced and manipulated into prostitution.

"We would encourage property hosts or nearby residents to remain vigilant and report any activity that appears unusual or suspicious at short-term rental premises.

"We rely on the intelligence that we receive from the public and even the smallest piece of information can help us to build a picture that may be the crucial missing link to an investigation."

The signs include a large number of women regularly being brought to and taken from the property, closed curtains or blacked out windows and different men staying for short periods.

Police released the information to coincide with Anti-Slavery Day (Fri).