The council is ramping up its efforts to tackle the slave trade – by enlisting the support of legitimate local businesses.

The Trading Standards team believe many bogus doorstep workers are illegal immigrants working for gang bosses who are raking in all the money.

In one recent incident they discovered workers living in horrendous conditions in dilapidated caravans.

The Trading Standards team have made up business cards which they are distributing through builders’ merchants and other places – including burger vans and hot roll shops– that workmen frequent.

And they want as many honest builders to get in touch when they come across fraudulent workers who are operating in their area.

Scott McKenzie, Senior Manager of Protective Services, said: “It is a horrible and despicable crime and the team here are passionate about eliminating it as much as possible.

"There is also the larger scale operation. Some of the workers involved in this criminal activity are themselves “slaves”. They are mostly illegal immigrants forced to live in terrible conditions and to work for no money.

"The “Boss” can be earning up to £20,000 a day and will be a millionaire. There is only person benefitting from this misery and we want this to stop."