David Cameron has launched an inquiry into trade union tactics after the dispute which almost led to the closure of the Grangemouth oil refinery.
The review, headed by Bruce Carr QC, will examine whether the law needs to be tightened up to prevent “intimidation” and “harassment”.
It follows claims the Unite union sent a “mob” to the home of a refinery manager during the recent dispute.
Unite said it would not co-operate with the inquiry as it was a “Tory stunt”.
The union has defended its use of so-called leverage tactics, where managers are directly targeted as part of a protest, and argued that bad employers should have “nowhere to hide”.
Cabinet Office Minister Francis Maude said such tactics had no place in industrial relations – but denied that the inquiry was politically-motivated.
“It’s not about politics, this is about the national interest,”
He said “protest is fine” but it should not be allowed to move over “into intimidation and clearly inappropriate activity,” with the management being treated as “the enemy”.