Last week The Herald revealed that websites such as Craigslist featured adverts from private landlords in Scotland targeting vulnerable women by offering free rent in return for sex.

Raising the issue at First Minister’s Questions, Scottish Labour MSP Claire Baker said: “We know sex for rent adverts have been posted online for properties in Scotland, but we have no way of knowing how many tenants are currently in such arrangements.

“The practice opens the door to vulnerable tenants, who are often facing homelessness and poverty and who find themselves in commercially exploitative arrangements.”

Ms Sturgeon told MSPs that housing minister Kevin Stewart had written to the website asking them to take action.

She said: “I was extremely concerned – horrified, actually – to read the reports that the member refers to.

“As a government, we are already taking action to tackle such issues through the implementation of equally safe, which is our strategy to tackle any violence against women and girls.

“We are also taking action to improve the availability of and access to housing for everyone, and action to tackle the poverty and inequality that can so often render people vulnerable to being exploited in such a way.

“Let me assure the member we will look carefully at what action we can take, further to what we are already doing, across all those areas.

“The minister will be very happy to meet the member to discuss that in more detail, if that would be of interest to her.”

Green MSP Patrick Harvie said he was aware that not all such cases involved a registered landlord.

But he added: “Isn’t it pretty clear that any such exploitative arrangements should lead to an automatic fail of the fit and proper person test and revocation of any existing landlord registration.”

Nicola Sturgeon agreed, saying: “I struggle to see how anyone who placed an advert of this description would pass the fit and proper person test.”

She said the housing minister would continue to investigate the matter.