The Bank of England will take centre stage in the increasingly bitter EU referendum battle after it signalled concerns that the vote could trigger panic in financial markets.
Governor Mark Carney is giving evidence to MPs following the announcement that protection for institutions will be bolstered during the period of the crunch vote.
Firms will be given three additional opportunities to bolster their liquidity reserves with central bank assets, two shortly before the poll on June 23 and one shortly after.
A statement setting out the indexed long-term repo (ILTR) operations said: "The Bank will continue to monitor market conditions carefully and stands ready to take additional action if necessary."
Mr Carney, who has already warned of potential headwinds facing the economy, is expected to be pushed hard over his assessment of Brexit risks when he appears before the Treasury Select Committee.
His deputy Sir Jon Cunliffe - formerly the UK's permanent representative to the EU - will also give evidence.
Campaigners for leaving have insisted the biggest risk to the UK economy is "sticking with an unreformed EU" and accused Remain of mounting "Project Fear" to win the referendum.
But Will Straw, executive director of the Stronger In campaign, said: "We've already seen the sensitivity of the pound to the prospect of leaving the EU and now we learn about the very real prospect of lending drying up.
"When the Bank of England issues this kind of warning, everyone should sit up and listen."
The Bank's move came as the row over the departure of John Longworth as director general of the British Chambers of Commerce continued to rage. Mr Longworth quit after voicing his "personal" view last week that Britain would be better off outside the EU.
Downing Street has vehemently denied claims that it pressured the BCC - which has taken a neutral stance on the referendum issue - into forcing him out. But reports suggest No 10 aide Daniel Korski telephoned Mr Longworth hours before he was suspended by the organisation, demanding an explanation for his comments.