Willis Chairman and CEO Joe Plumeri is a fast-talking, streetwise New Yorker. So is Larry Silverstein, the leaseholder of the World Trade Centre. Mr Silverstein didn’t get to where he is today – he’s a billionaire – without knowing how to use the courts. That’s why Mr Plumeri and Willis will be carefully examining evidence Mr Silverstein presented in a New York court last week that alleges Willis, his broker, guaranteed he could claim more than $7 billion if both WTC towers were lost.

September 11 brought the whole issue into sharp focus when the unthinkable happened. The panel of insurers covering the WTC say they didn’t agree to any such clause in the policy. As far as the insurers are concerned, the WTC was covered for half that amount – the equivalent of one tower. The argument revolves around whether the aircraft that hit the towers were one event or two.

According to the twin towers’ insurers – Swiss Re, AIG, Allianz and Chubb – Willis didn’t tell them the coverage included two payments in the event of a double disaster.

The allegations continue to roll, with Swiss Re claiming Mr Silverstein pressured Willis into supporting his “two occurrences” belief. Moreover, they believe that the Willis broker responsible for the twin towers policy stated the day after September 11 that the policy counted the events as one attack.

So far Willis and Mr Plumeri have kept relatively quiet. But expect the erudite New Yorker to say his piece when the time is right.