PRIME Minister David Cameron called blacklisting unacceptable as his Government said it had not seen evidence that would require a probe into the practice.

His comments came after allegations that members of the security forces and police were involved in drawing up lists that locked hundreds of workers out of jobs on construction sites.

Labour challenged the UK and Scottish Government to ensure blacklisting did not take place on any of their major projects. The party has warned the practice may still be taking place.

Downing Street said it had not seen evidence "that would require an inquiry".

Mr Cameron's spokesman said the Prime Minister would encourage anyone with evidence to take it to the Information Commissioner.

MPs have heard evidence some workers were targeted over union affiliations, or for being members of the Labour party. Union Unite has called for an inquiry.

Labour MP Ian Lavery said blacklisting "destroyed the lives of many innocent people".

Many have no idea they were included on a list compiled by a group called the Consulting Association, found when the Information Commissioner's Office (ICO) raided it in 2009.

Shadow Business Secretary Chuka Umunna said: "There are sufficient questions to justify the Government carrying out a full investigation into the extent blacklisting took place and may still be taking place, at the very least on public sector projects.

"The Government should then set out what practical steps may be needed to stop blacklisting and blacklisting checks happening on public projects."

Kate Devlin