Det Insp Ben Henley, from the force, said: “One of the main challenges we had was that we were reliant on victims coming forward, which was, unfortunately, very rare.

“So the STIM has been really beneficial for us.

“We’ve utilised the STIM to score over 128 online adverts, and this has resulted in 40 visits being conducted at locations, with dozens of individuals safeguarded.”

He said the tool had been identified as “national best practice” for police forces.

Critics have said STIM uses imprecise risk indicators that expose independent sex workers to arrest.

However, Dr Xavier L’Hoiry from the University of Sheffield said the tool, which analyses language, photographs and other details, had “delivered many benefits to users”.

He said: “Previously, organisations would need to look through thousands of adverts online manually, which can take a massive toll on those doing the work.

“The STIM still relies on human intervention but it aims to make the risk assessment process much quicker and straightforward for those involved.”

Sixteen UK police forces have adopted STIM, as well as two UK charities, four police forces abroad and the Danish Centre Against Human Trafficking in Denmark, Dr L’Hoiry said.