The Prime Minister and the Unite union were embroiled in fresh clashes after David Cameron said the Government will consider action to stop cases of “industrial intimidation”.
His warning came amid continuing attacks against Unite over claims it intimidated bosses from the Grangemouth refinery in Scotland during a bitter dispute over pay and conditions and links between a convenor and the selection of a Labour candidate in Falkirk.
During Prime Minister’s Questions on Wednesday, Mr Cameron accused Labour of “ducking its responsibilities” by failing to order an investigation into claims against Unite.
The Prime Minister told MPs he was shocked by allegations children of executives had seen “wanted” posters put through their letter boxes, while their neighbours had been told they were “evil”.
Unite said the continuing attacks masked an agenda to “protect the rich and the powerful at the expense of working people’s right to freedom of expression”.
A union spokesman said: “Protest is about the freedom of expression. That is what David Cameron is threatening.
“Ordinary working people do not have the benefit of national newspapers or the floor of the Commons when it comes to expressing their views. Now it seems the Tories want to gag them.
“All Unite-organised protests have been lawful. None have breached the right of privacy. All have been conducted silently when at a place of residence.
“No one, least of all children, has been intimidated. Their purpose has been to ensure the community knows how workers are being treated and to ensure companies act within moral parameters.
“This is not an attack on Unite. It is an attack on freedom from a government devoted to protecting the rich and powerful at the expense of everyone else.”