Cameron orders inquiry into union tactics in wake of Grangemouth

However, in a sign of renewed coalition tensions, the Liberal Democrat Business Secretary Vince Cable made clear he had only agreed to the inquiry on the basis that it would also examine the practices of employers, such as the "blacklisting" of workers.

And his party colleague Danny Alexander, the Treasury Chief Secretary, has  indicated the Lib Dems will only agree to any recommendations to change the law if they were convinced they would lead to an improvement in industrial relations.

The Unite union dismissed the review as a "Tory election stunt" and warned that no trade union would be prepared to "collaborate" with it.

The review follows claims that Unite sought to intimidate executives from Ineos, the refinery's owners, including sending "mobs" of demonstrators to protest outside their homes and premises associated with Ineos chairman, Jim Ratcliffe.

In recent weeks the Prime Minister has repeatedly attacked the union in the Commons, challenging Labour leader Ed Miliband to hold an inquiry into claims of vote-rigging in the Falkirk constituency party in an attempt to secure the selection of Unite's favoured candidate for parliament.

Unite general secretary Len McCluskey has always denied any intimidation or bullying on the part of the union, insisting that it was acting within the law.

As part of his remit, Mr Carr will consider whether existing laws are sufficient to prevent what Government sources described as "inappropriate or intimidatory actions" in trade disputes as well as the response of the police to complaints.

More generally, the review will look at the underlying causes of industrial relations difficulties in affected industries, the potential impact on the UK's critical national infrastructure and the consequences for investor confidence in key sectors.

It will also make recommendations on the respective roles of government, employers and employee representatives in ensuring effective workforce relationships.

Cabinet Office Minister Francis Maude, a Conservative, said: "Allegations about trade union industrial intimidation tactics, including attempts to sabotage businesses supply chains and harass employers' families are deeply concerning.

"That's why we need an independent review to get to the bottom of these activities, as well as to look at the role played by government, employers and employees in industrial disputes.

"This forms part of our long-term plan to ensure Britain remains competitive and to secure an economic recovery for hard-working people."

Mr Cable, in contrast emphasised that Britain had generally enjoyed good industrial relations for the past two decades while strikes were at a historically low level.

"There were clearly some very serious matters going on in Grangemouth. That is why I have agreed to a proportionate and rational review of industrial disputes, including leverage and other tactics used by both unions and employers," he said.

"There are rogue unions but there are also rogue employers, some of whom have in the past engaged in illegal tactics like blacklisting. This Government will tolerate neither"

And in a further sign of coalition tensions, his party colleague Mr Alexander has said that the inquiry should not be used as a vehicle for "union-bashing".

"If there are measured, sensible, prudent reforms that could help to improve the industrial relations landscape yet further, I'd be up for that. What I'm not up for is a bunch of union-bashing," he told Sky News's Murnaghan programme.

"It is a balanced and impartial inquiry looking into what goes on in industrial disputes to see whether the law is adequate.

"This is not saying that everything is wrong. It is saying there's been some evidence provided, some allegations made and so-called leveraged practices which involve in some cases quite unpleasant examples of intimidation against fellow workers and against management. That's not acceptable.

"We need first of all to establish the facts and then to see whether the law needs changing."

TUC head of employment rights Sarah Veale, who appeared on the same Murnaghan programme, dismissed the inquiry, insisting that it was clearly "politically driven".

She said: "It is a completely disproportionate response to one or two instances. It is really quite disgraceful that the Government is pretending that there is a real public interest concern here. There isn't."

A Unite spokesman said: "This review is a sorry attempt by the coalition to divert attention from the cost of living crisis. Vince Cable may not have noticed but the Grangemouth dispute has been settled. This review is nothing more than a Tory election stunt which no trade unionist will collaborate with."

GMB general secretary Paul Kenny said: "At a time when living standards are falling, when people are struggling to pay energy bills, when executive pay is rocketing and when investment in industry by cash rich employers has fallen through the floor this announcement seems like another sop to the Tory backbenches.

"One of the questions that needs to be answered about Grangemouth is how could one man (Mr Ratcliffe), a non resident at that, be able with impunity to hold the country to ransom by having the unfettered power to shut down a facility vital to the well being of the nation and the economy of Scotland. That is the real scandal at Grangemouth.

Mr Carr, a leading industrial relations lawyer, will head a three-strong panel sitting alongside one representative each from the employers and the unions.

They will be supported by a secretariat made up of officials drawn from the Cabinet Office, the Department for Business Innovation and Skills, and more widely across government.

Once the panel is in place, it will be tasked with gathering evidence and producing recommendations within six months. It will report jointly to Mr Maude and Mr Cable.

Shadow health secretary Andy Burnham said he wanted reassurances that the move was not a "political call".

He told BBC One's Sunday Politics show: "Of course if there's been intimidation it's unacceptable and that should apply to unions as well as employers.

"I think I need reassurance that this isn't a political call by Mr Cameron designed to report near the election, so you know we'll see how this develops."

Scotland's First Minister, Alex Salmond, criticised the the UK Government plan.

"The Scottish Government has not been consulted on this review and regret the way it has been announced by UK minister," he said.

"There are of course legitimate issues that should be addressed in relation to industrial relations and the operation of our key national infrastructure. However, to allow such an important matter to be presented as a political manoeuvre is foolish and irresponsible.

"There are also internal issues for the Labour party to sort out, with regard to how they allowed an internal selection battle in Falkirk to spill over into industrial relations in Grangemouth, to the great detriment of the workforce and potentially the entire Scottish economy.

"However, these are properly matters for the Labour party.

"The way UK ministers have approached this issue suggests that their interest is less about industrial relations and almost entirely about seeking electoral advantage.

He added: "Finally, on the remit of this review. Police Scotland is more than capable of administering the law. They act impartially and there must be no attempt to politicise their role. Indeed, the Scottish Government will not allow that to happen.

"The key to successful industrial relations is co-operation and understanding between employer and employee. The role of government is to foster that atmosphere which means that you have to be trusted by both. The Scottish Government is. The UK Government is not."