By Simon Mundy and Jeremy Grant

Icap, the world?s biggest interdealer broker by trade volumes, would move its main operations away from London ?extremely rapidly? if faced with a European financial transactions tax, its chief executive has warned.

Michael Spencer told an analysts? conference call on Thursday that ?the wholesale financial market will evaporate from Europe? if the levy were introduced.

His remarks came a day after Jos? Manuel Barroso, president of the European Commission, outlined plans for a tax of up to 0.1 per cent on financial transactions, which he said could raise an annual 55bn euros (?48bn).

Mr Spencer – who also said he would consider a bid for the London Metal Exchange – labelled the plan ?deluded?, adding that he expected the UK to veto what he called ?a tax on the City of London for the benefit of the eurozone?.

?Sadly, if it [is implemented] we will just have to relocate our business,? said Mr Spencer, a former treasurer of the Conservative party.

?Icap is the biggest foreign exchange broker in the world – our business would evaporate if we did not move its domicile, which we would do extremely rapidly.

?You and I will be relocating for sure from the City of London,? he added.

Mr Spencer added that he would give ?consideration? to a takeover of the London Metal Exchange, which has already received expressions of interest from at least 10 suitors.

The exchange, which supports futures trading on a range of base metals, expects to open its books for inspection in early December.

?It is a very good business,? Mr Spencer said. ?It?s quite a complex business to fully understand, but it is . . . worth looking at and we will look at it.?

He spoke after Icap announced it had secured four investment banks as equity partners in its iSwap interest-rate swap platform, boosting its hopes of taking a lead in the emerging business for electronic broking of over- the-counter derivatives.

Barclays Capital, Deutsche Bank, JPMorgan and Bank of America Merrill Lynch will all take undisclosed stakes in iSwap, and there was ?potential for investment by other user banks?, Icap said.

It is vying for dominance in electronic swaps with Tradition?s Trad-X platform and others from Tullett Prebon and GFI Group.

Icap said revenue for the six months to September would be marginally ahead of the ?867m in the same period last year.

? The Financial Times Limited 2011