An inquiry into the tactics used by trade unions during the Grangemouth strike has been scaled back, according to the Daily Mail today.

David Cameron asked Employment expert Bruce Carr QC to lead a review after Unite was accused of bullying bosses at Grangemouth refinery in Scotland last year.

Mr Carr had been due to make his recommendations this autumn. But yesterday he said he was ‘increasingly concerned’ about a lack of testimony from employers or unions. He said he would still produce a scaled-down report, but would make no legal suggestions. He  also added that in the run-up to the general election, he was concerned that any recommendations ‘would be capable of being construed as the review making a political rather than an evidence-based judgement’.

A senior Conservative member said: ‘It’s deeply disappointing that union bosses like Len McCluskey have refused to co-operate.’

However, Len McCluskey, general secretary of Unite, the country’s biggest union said: “The Tories have spectacularly shot themselves in the foot on this. In their haste to attack trade unions, they have embarrassed their own appointee, Bruce Carr, into accepting this report for what it was all along – a desperate pre-election stunt to smear democratic trades unions and their members.

“This was always a purely political exercise with neither the CBI nor the TUC prepared to get involved.  Now Bruce Carr has moved to distance himself from what was nothing more than a pre-meditated effort by the Tory party to get a QC to sanction laws further restricting the rights of unions.

“The UK’s trade unions are already the most highly regulated in the world, leaving the UK’s workers among the easiest and cheapest to sack.  But while Bruce Carr may have thrown in the towel, the Tories remain intent on going into the general election in 2015 with a vicious anti-worker programme.

“Now at least voters can see their agenda for what it is – a determination to impede all protest against unethical behaviour by employers, and the removal of the last vestiges of protection against abuse that the working people of this country possess.”

Mr Carr was asked to review the effectiveness of the current laws to prevent ‘inappropriate or intimidatory actions in trade disputes’.

But after four months of trying to gather evidence, he said: ‘I have become increasingly concerned about the quantity and breadth of evidence that the Review has been able to obtain from both employers and trade unions relevant to its terms of reference.’ He added: ‘Any recommendations which might be put forward without the necessary factual underpinning would be capable of being construed as the review making a political rather than an evidence-based judgment, whichever direction such recommendations might take.’

The dispute began last October when Ineos said that the Grangemouth plant was losing £10million a month, and ordered a survival plan requiring staff to take a cut to their pensions.

However, the plant’s 1,300 staff refused and so Ineos announced the closure of the plant, triggering major job losses.

Following talks and a brief shutdown, the unions accepted a survival plan involving a new pension scheme and agreed not to take strike action for three years.

Ineos petitioned ministers to criminalise trade unions that use ‘thuggish’ tactics – and extend the notice period for strikes at large manufacturing plants for safety reasons. Unite claimed this was not within the review’s remit.