Royal Bank of Scotland has drawn up plans to shift its head office from Scotland – where it has been based since 1727 – in the event that next week's independence referendum backs a break away from the rest of the UK.

The announcement followed news that Lloyds Bank would also move its head office to England and a warning that mortgage lenders are preparing to restrict lending in the event of a yes vote as concerns deepen over the currency that an independent Scotland would use.

Treasury sources had indicated on Wednesday night that such a move by RBS was likely after the other bailed-out bank with major operations in Scotland, Lloyds Banking Group, revealed it too would set up legal entities in England to protect its credit rating.

The moves by the banks, which received £65bn of taxpayer bailouts in 2008 and 2009, follows a warning by another pillar of the Scottish financial community – Standard Life – that it would shift business to England. BP has also spoken of its concerns.

Sir Charlie Mayfield, the chairman of the John Lewis Partnership, is the latest leading business figure to step into the debate, warning on Thursday that prices will rise in Scotland if it breaks away. But the employee-owned retailer does not intend to reduce its commercial operations in Scotland, where it has nine stores, a contact centre and more than 3,000 employees.

The Bank of England governor, Mark Carney, faced intense scrutiny on Wednesday from MPs on the Treasury select committee about the financial implications for an independent Scotland.

He stressed that Threadneedle Street had contingency plans in the face of concerns about capital flight from Scotland and indicated that a Scottish central bank could need at least 25%, and possibly more than 100%, of the nation's GDP in reserves if the first minister, Alex Salmond, decides to use sterling after independence without the support of Westminster.

The precise amount of reserves needed to back an independent Scotland will depended on the size of the banking sector, at least 10 times the size of Scottish GDP.

There had been mounting expectations that banks would shift their registered offices to seek the protection of the Bank of England – to protect customers and the bank's all-important credit ratings.

Carney promised to provide a detailed analysis to the committee on Thursday morning of his comments on the approach taken by other countries.

In a statement issued last night, Lloyds – which owns Bank of Scotland and is 25% owned by taxpayers – spelled out its contingency arrangements, which would be likely to involve moving its registered office from Scotland, where its Halifax Bank of Scotland business is registered. "While the scale of potential change is currently unclear, we have contingency plans in place which include the establishment of new legal entities in England," it said.

"This is a legal procedure and there would be no immediate changes or issues which could affect our business or our customers," added Lloyds, which is the largest private-sector employer in Scotland with 17,000 staff.

RBS said on Thursday: "As set out in the risk disclosures in RBS's annual report, there are a number of material uncertainties arising from the Scottish referendum vote which could have a bearing on the bank's credit ratings, and the fiscal, monetary, legal and regulatory landscape to which it is subject. For this reason, RBS has undertaken contingency planning for the possible business implications of a yes vote. RBS believes that this is the responsible and prudent thing to do and something that its customers, staff and shareholders would expect it to do.

"As part of such contingency planning, RBS believes that it would be necessary to redomicile the bank's holding company and its primary rated operating entity (The Royal Bank of Scotland plc) to England. In the event of a yes vote, the decision to redomicile should have no impact on everyday banking services used by our customers throughout the British isles.

"However, RBS believes that it would be the most effective way to provide clarity to all our stakeholders and mitigate the risks previously identified in our annual report."

Banks are also thought to be devising other contingency plans. One source said they may transport more bank notes to Scotland to "ensure appropriate liquidity" if customers want to withdraw more cash in the event of a yes vote.

One housing industry insider said there has already been an impact on the housing market, with signs that the market for homes worth more than £600,000 – the top end of the market in Scotland – is drying up. At the same time, commercial property deals were being put on hold until the vote was known – and could be abandoned in the event of a yes vote.

Some potential property buyers have inserted clauses into their offers saying "subject to a no vote", according to the mortgage broker Ray Boulger of John Charcol. He said: "A yes vote will create massive problems in terms of how mortgages are denominated and regulated. We expect it to be much more difficult for Scottish borrowers to get mortgages post a yes vote."

Other bankers are speaking of a pause in lending until the situation is clear. Lenders are refusing to comment publicly for fear of being accused of playing politics. But one said: "Before that poll [the Sunday Times/YouGov poll that showed the yes campaign in the lead] it was interesting but not critical. Now we are watching things very, very closely. It – introduces huge uncertainty and one way of decreasing our exposure and risk would be to reduce the loan-to-value offered to borrowers."