Charges for separated parents to arrange child support payments are handing the Government almost £1m a month, it has emerged.

The SNP has condemned the “cruel and callous tax” involved in using the Child Maintenance Service (CMS), highlighting the impact on mothers escaping domestic abuse.

Figures obtained by the party show that the charges have earned the Government more than £11m across the UK since they were introduced in 2014.

However, they also show the sums involved are on the rise – bringing in around £950,000 in March, the most recent month for which figures are available.

They are expected to continue to rise as more maintenance cases are switched over from the scrapped Child Support Agency, which will shut down completely in 2018.

Angela Crawley, the SNP’s spokeswoman for children, women and equalities, said domestic violence survivors would fear giving their abuser personal bank details, forcing them to use the service.

She said: “It is near impossible for women who have escaped abuse to share details with an ex-partner.

“These unfair charges will disproportionately impact survivors of domestic abuse, who feel they have no option but to use the service as they are too frightened to have a direct link to their abuser.

“I am very concerned that this is a cruel and callous tax on child support and that ultimately it is the children who will lose out on money intended to support them.”

But a spokesman for the Department for Work and Pensions (DWP) said the charges made only a “very modest contribution” to the costs of running the service.

The CMS introduced three charges: a £20 application fee for using it, enforcement charges for non-payment, and a “collect and pay” fee for those who ask the service to administer the payments.

Under collect and pay, parents must hand over 20 per cent on top of their usual child maintenance amount – while receiving parents must pay a 4 per cent collection fee.

Crucially, the application fee can be waived for domestic violence victims – around a third of applicants are given the exemption – but no such exemption exists for the collection service.

A written parliamentary answer to the SNP revealed the Government has received £11.2m from the time the charges were introduced in June 2014, up until March 2016.

Of that sum, no less than £8.6m came from collect and pay services, with just £2.5m coming from application fees – and only £140,000 from enforcement.

Campaigners including the Gingerbread group have called for child maintenance charges to be scrapped for single parents, to fight poverty.

But the DWP spokesman said: “We encourage parents to pause and consider the different options available before applying to the service by default.

“We also actively pursue those parents who fail to meet their financial responsibilities and, in nine out of 10 of cases, parents are paying towards the money owed.”

Running child maintenance services costs the Government around £230m a year, with more than £3.5bn outstanding from payment arrears.