Fresh controversy over the blacklisting of construction workers has flared after news that a committee of MPs is to look into new allegations that union members are being denied work in the construction industry.
The chairman of the Scottish Affairs Select Committee, which has been conducting a lengthy inquiry into the issue, raised the prospect of further hearings into new revelations of a secret register of workers.
A company accused on Danish TV last week of blacklisting workers who joined a union, strongly denied the allegation.
Atlanco, which has an office in Northampton, said the claims were "without merit and entirely false".
The select committee has held a series of meetings following the discovery of a blacklist of more than 3,000 mainly construction workers in the UK five years ago.
Some of the companies involved have launched a scheme to pay compensation, although no money has yet been paid out.
The committee made a series of recommendations in a previous report, including calls for compensation from companies which used the blacklist before they were considered for public contracts, and direct employment in the industry, with less use of agency workers.
Committee chair Ian Davidson (Labour/Co-op, Glasgow South West) said: "We are very disappointed that the Government has rejected our recommendation for direct employment on all publicly-funded construction projects and for transparent recruitment and employment practices - even though they have asked us to take more evidence.
"What we have seen shows clearly that the use of agency workers is a weak spot in eradicating blacklisting and we therefore recommended that direct employment and transparent recruitment practices should be standard for all public sector contracts in the construction industry.
"This concern has been vindicated with the recent allegations that an international employment agency that operates in the UK has been blacklisting employees, using a secret register to prevent workers who complain about pay or who join a trade union getting further work.
"I will be asking the committee to look at these new revelations with a view to further hearings.
"The committee will also shortly be reviewing the process of negotiations, between the companies already found guilty of blacklisting and representatives of their workforces, to ensure that both sides are giving the need for a fair and commensurate settlement the urgency it deserves."
Steve Murphy, general secretary of construction union Ucatt, said: "The latest blacklisting allegations demonstrate why direct employment and cutting down the use of agencies is vital to stamping out this practice.
"The Government's response demonstrates that they do not care about the victims of blacklisting or in stopping blacklisting from occurring."
GMB national officer Justin Bowden said: "We know that the employers lied as well as spied.
"For more than a decade they lied about the existence of blacklisting whilst systematically denying employment to a generation of health and safety reps and shop stewards.
"Since then they have applied the same systematic approach to schmoozing politicians and others into believing that blacklisting was a thing of the past.
"These new revelations blow that out of the water. The sooner these miscreants are in front of the Scottish Affairs Committee accounting for their actions the better, but where they should really be is behind bars."
Unite assistant general secretary Gail Cartmail said: "The Government is not learning the lessons of previous blacklisting scandals and these latest revelations point to the urgent need for action to stop blacklisting from taking root again.
"The Government's refusal to support the Scottish Affairs Committee's recommendations on direct employment, self-cleaning and importantly employing blacklisted workers points to complacency and is deeply disappointing.
"This needs to be complemented by a full public inquiry into blacklisting and the activities of major construction employers who still to this day restrict trade union activities in major construction sites, leading to poor practices, health and safety risks and increased fatalities."
A Business Department spokesman said: "We are clear that blacklisting is an unacceptable and illegal practice, and we take any allegations of blacklisting very seriously.
"Blacklisting legislation was strengthened in 2010 to deal with this serious offence.
"Government also increased the penalty the Information Commissioner's Office (ICO) can impose for serious breaches of the Data Protection Act to £500,000."
The company at the centre of the new claims said in a statement: "The allegations directed at Atlanco ApS in the programme O starbejdernes Bagmaed are without merit and entirely false.
"Clear evidence that we presented to the producers disproving each of their assertions went ignored. Further, additional statements that we submitted refuting their claims were not included in the programme that aired.
"We are extremely disappointed by DR's irresponsible and reckless actions. To that end, we are actively pursuing our legal recourse in response to their defamation of our company.
"To be clear, there is no blacklist or 'secret database' of any kind, nor is there any discrimination against any workers who wish to be active in a union.
"Atlanco has absolutely no issue with workers being members of a union and fully respects such membership."