British bankers reacted furiously last night to Irish banks cold-calling their customers in an effort to poach their deposits after the controversial guarantee issued this week by Dublin. An estimated £400 billion of corporate deposits is sloshing around the British banking system and is regarded as vulnerable to attack from foreign banks.

Corporate treasurers are more active than personal customers in moving deposits. Before the credit crunch, billions were shifted around the world seeking highest yields, but treasurers are now more concerned about safety.

One relationship banker in a big UK bank said: “They were rate tarts, now they are safety tarts.” His corporate clients were raising the Irish issue, he said, either to move money to Irish rivals or to try to win a higher interest rate. Not much has yet been withdrawn, he said, but that was in part because of the maturity profile of deposits, which could not be withdrawn instantly, and slow back-office systems.

One corporate treasurer with £400 million on deposit with various banks was cold-called by a big Irish bank this week, according to Martin O’Donovan, of the Association of Corporate Treasurers. Irish banks appeared to be using the Irish guarantee of all deposits for two years as a marketing tool, he said. The Irish Government has an AAA rating. A UK banker said: “They see it as a big marketing opportunity – understandable on a micro level, but outrageous on a macro level as it threatens stability of the system.”

Corporate deposits in Britain are not covered by the Financial Services Compensation Scheme. It lifted its maximum guarantee from £35,000 to £50,000 yesterday, but only for the savings of individuals and sole traders.

Irish Nationwide has been marketing itself to potential clients as “the safest place to deposit money in Europe” in an e-mail from Michael Fingleton Jr, son of the chief executive. A Department of Finance spokesman confirmed that the e-mail had been referred to the Financial Regulator in Ireland.

The e-mail said that deposits attracting fixed-term interest rates of 6.75 per cent and 7.1 per cent were guaranteed regardless of size and were the best value in the UK market. Irish Nationwide described the incident as “inappropriate and regrettable”. The British Bankers’ Association has formally complained to Ireland about the problem.

Ireland is expected to be chided for its unilateral bank deposit guarantee scheme by Gordon Brown and other leaders of Europe’s biggest economies when they meet in Paris today. President Sarkozy, of France, who has the called the meeting, is hoping to get agreement that European Union nations should act in concert before intervening to prop up their own banks.

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