By Charles MaggsFollow @charlesmaggs
Trade unions have received at least £113 million from the state through government-funded full time trade union officials, according to research by the Tax Payers Alliance (TPA).
Over 3,000 public sector staff worked on trade union activities whilst on the state payroll.
Cabinet Secretary Francis Maude acknowledged the report and told politics.co.uk that work was being done to reduce the cost.
"For too long there has been insufficient monitoring of union work done by civil servants during their working hours," he said.
"Some civil servants were able to spend years doing nothing but trade union work. That isn't fair to the taxpayer or other civil servants.
"That's why we are limiting the amount of time civil servants can spend on trade union work and introducing a benchmark which will slash the cost of facility time to the taxpayer."
But Matthew Sinclair, chief executive of the TPA believes that no public money should be going towards trade union activities.
"It is simply wrong that taxpayers are seeing their money used to pay thousands of trade union activists who organise strikes which disrupt the services they rely on and pay for handsomely," he said.
"Thousands of staff who should be working for public services are working for the trade unions instead."
Maude's plans are unlikely to satisfy the Tory right, including back bencher Jessie Norman who tabled a motion last year calling for a reimbursement to theTreasury for money paid to union reps for their non-work related activities.