The European Central Bank is on track to deliver a record-breaking “stimulus by stealth” to the eurozone economy on Wednesday, as the first-ever offer of unlimited one-year funds could see demand running into several hundred billion euros.

The size of the ECB’s emergency liquidity-boosting operation, which was announced last month, is expected to be bolstered dramatically by the belief in financial markets that eurozone official interest rates will not fall – and the opportunity to borrow on such favourable conditions will not be repeated.