The call was put forward by construction union Ucatt and backed unanimously by conference delegates.

Ucatt general secretary Alan Ritchie said: “Blacklisting is one of the biggest crimes against society.

“But it is not just the worker this affects. Often that individual is the main breadwinner of the family. You put a whole family on the breadline.”

The industry was rocked by the blacklisting scandal last year when an organisation called the Consulting Association was found to hold a blacklist of over 3,000 construction workers.

More than 40 major construction companies were using its services.

In March this year, the Government introduced regulations that were designed to outlaw blacklisting but they have been attacked by the unions for being too weak.

The UCATT motion binds the TUC and the union movement to campaign for stronger legislation that will ensure that blacklisting is finally outlawed.

This legislation will make blacklisting a criminal offence, require that if a worker’s name appears on a blacklist they are officially informed and receive automatic basic compensation.

The motion also calls for the definition of who is protected from blacklisting to be widened.

Ritchie said: “To stamp out blacklisting it must be a criminal offence. If employers are prepared to blacklist a worker and force them out of an industry. That is criminal.”