ROYAL Bank of Scotland’s treatment of small businesses may be the “largest theft anywhere” as it carved up firms like a “Sunday roast” because they wanted to move or make a complaint, MP’s have heard.

The lender’s controversial global restructuring group (GRG) was “more like an abattoir” where firms were taken apart as part of an “intended and co-ordinated strategy” to raise funds.

The GRG was set up as the bank’s turnaround unit for struggling businesses but was disbanded in 2014 amid allegations of grievous customer mistreatment.

READ MORE: Investors suing bank claim 'failing firm' policy came from RBS bosses

RBS has already put aside £400 million to compensate customers and launch a new complaints system relating to “complex” fees and dealings with its debt restructuring unit between 2008 and 2013.

But MPs are now calling for criminal charges to be brought against the bankers at the unit which had 12,000 small businesses as clients at one point, with most going on to be liquidated.

Yesterday, the GRG was widely condemned in a House of Commons debate which called for an independent inquiry into the treatment of businesses by all financial institutions.

Shadow Treasury Minister Clive Lewis said: “We do know that 90 per cent of GRG administered businesses never made it back to mainstream banking. This is a very high proportion.

“The cost of this is immeasurable, but we believe it to be in the tens of billions. So let’s be clear here. This is the potential size of the injustice that has taken place in our country.

“If it is this big, it may be the largest theft anywhere, ever.”

READ MORE: Investors suing RBS claim ‘killing floor’ policy came from top bosses

MPs also heard that businesses were “carved up like a Sunday roast” and only placed in GRG because they wanted to move banks or had made a complaint.

Mr Lewis added: “This was meant to be somewhere where they were put back to try to get them into a situation where they would come back as a viable business. Actually, it was more than an intensive care unit, it was more like an abattoir, where they were actually stripped and taken apart.”

Ahead of yesterday’s debate the Treasury Select Committee published a memo sent to GRG staff in 2009.

It told staff that “sometimes you need to let customers hang themselves”, under the heading “rope”.

Tory MP and committee chairwoman Nicky Morgan said the memo “lifts the lid on a culture at RBS”.

The bank admitted in November 2016 it “did not meet the standard it set of itself which impacted on how it treated some of its SME customers”.

It followed the City watchdog’s publication of an initial summary of a report into the activities of GRG between 2008 and 2013.

Analysis: Fresh focus inflicts further damage on bank’s already battered image

RBS was accused by the Financial Conduct Authority of “systematic” failings at its GRG which led to the mistreatment of thousands of small business customers.

The bank said as many as 4,000 of the 12,000 customers transferred to the bank’s GRG unit between 2008 and 2013 are eligible for compensation.

Shadow business minister Bill Esterson said: “There are many ... who believe criminal investigations to be the appropriate way forward at RBS GRG.”

Treasury Minister John Glen said he will “stop at nothing” to help small and medium-sized businesses “failed” by RBS and others.

He said: “I want to be really clear that in doing this job, in addressing the issues raised in the House today, that I will stop at nothing to improve the situation that we have had to date.”