The Westminster leader of the SNP has demanded that Theresa May summon the head of publicly-owned RBS to tell him to reverse proposed local branch closures.
Ian Blackford made the call at Prime Minister's questions today, accusing the bank of "turning its back on local communities".
But Mr Blackford struck a noticeably harder note with his demand of the bank - bailed out by the taxpayer after the 2008 crash - than his SNP Scottish government colleague, Paul Wheelhouse.
In an interview for Representing Border earlier this month south of Scotland MSP Mr Wheelhouse called for a pause in the closures but accepted the bank had to right to take "commercial decisions".
The row over branch closures was sparked by the bank's plans to close 32 branches across Scotland, many of them in rural areas.
From Annan to Eyemouth and Duns to Gretna, RBS is proposing to close 10 branches in the south of Scotland, saying it has evidence that more and more customers are turning to on line banking.
In the Commons today Mr Blackford demanded that the Prime Minister directly tell Ross McEwan, the chief executive of RBS, that the bank, still three-quarter owned by the state, should halt the plans.
Mr Blackford said: "If the Prime Minister recognises the importance of this, she should be summoning Ross McEwan into see her and making it clear that we will not accept towns and villages up and down the United Kingdom losing banking services.
"There are 13 towns in Scotland where the last bank will be going.This is not acceptable. It is about time the Prime Minister accepted her responsibilities. Will she summon Ross McEwan and will she tell the Royal Bank of Scotland this must be reversed?"
Mr Blackford pointed out that the UK had bailed out the bank in 2008 at a cost of £45billion.
He added: "Given we are the majority shareholder, will the Prime Minister step in and tell the Royal Bank of Scotland to stick to their commitment and not close the last bank in town?"
Mrs May replied: "The decision to open and close branches is a commercial decision taken by the banks, without intervention from the Government."
She added that she recognised "the impact this has on communities" and said the UK government had raised concerns that MPs have expressed on this issue in a meeting with RBS chiefs.
Mrs May's reply appears to be much closer to the approach taken by Mr Wheelhouse and the SNP Scottish government over the issue.
The SNP has stressed the Scottish government does not have powers over banking regulation, which lie with Westminster.
Under the arrangements put in place when the bank was saved its shares are managed by an arms length body, UK Financial Investments (UKFI), specifically charged with "managing these shareholdings commercially".
In an interview for Representing Border, I asked Mr Wheelhouse, the business minister, if Holyrood had the regulatory power would the SNP government be ordering UKFI to tell RBS not to go ahead with the closures?
Mr Wheelhouse told me: "Clearly commercial decisions are taken in the context of the regulations that applies to the whole industry.
"What we would like the UK government to do is to maintain a position where if there are branch closures that can only happen in a situation where you have some protection for basic banking facilities and that there are requirements to put something in in place."
He added: "We're not saying banks can't take commercial decisions. We recognise the commercial realities but what we want is to have that tempered by public interest in terms of the regulatory environment. That's all we're asking for.
"We think it's possible to have both the bank get the necessary changes it believes it has to make but also at a pace which the communities can absorb."