Insurance battle over Twin Towers

The leaseholder of the World Trade Center site is fighting his insurers in a New York appeals court over how much money he can claim after the attack of 11 September 2001.

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Larry Silverstein says the two aircraft that hijackers flew into the Twin Towers, killing thousands and flattening the iconic buildings, amount to two separate attacks.

That would give him $7bn (£4.4bn) instead of the $3.5bn which his insurers - led by Swiss Re and Travelers Property Casualty Corp - say he is due for what they believe constitutes a single attack.

A lower court has already ruled that the insurance policy the two sides agreed before 9/11 is ambiguous and needs to be adjudicated by a jury.

The argument over insurance is complicated by the fact that Mr Silverstein only took over the WTC six weeks before the attack, and the agreement insuring the site had not been finalised.

Cause or effect?

His lawyers say New York law makes clear that only the immediate circumstances can decide an insurance claim, not more distant causes.

"The first plane brought down the first tower, the second plane brought down the south tower," said Herbert Wachtell, one of Mr Silverstein's lawyers.

"If they are separate occurrences, time does not make a difference. Location does not make a difference," he said, hinting that a decision in favour of the insurers would cut into the funds available for rebuilding.

But the insurers say that following the bombing of the WTC in 1993, Mr Silverstein was keen to draw the broadest possible definition of "terrorism".

With only one cause, there was only one insured event, said Harvey Kurzweil, a lawyer for Travelers.

"We are talking about a highly coordinated military style precision attack," he said.

Mr Silverstein is also demanding that architect Daniel Libeskind, the man selected to design the WTC's replacement, should include more office and commercial space in his plans.