Families win right to sue World Trade Centre owners over 11 September attacks

The 49-page ruling by Alvin Hellerstein, a federal judge, was based on the cases of 70 of the injured and the families of those who died in the attacks. The judge said the Port Authority, which owned the World Trade Centre, "has not shown that it will prove its defence of governmental immunity as to negligence allegations made by WTC occupants".

The defendants had argued that the lawsuits against them should be dismissed because they had no duty to anticipate and guard against deliberate and suicidal aircraft crashes into the towers, and because any alleged negligence on their part was not the cause of the deaths and injuries.

Mr Hellerstein also said the evidence he had seen does not support Boeing’s argument that the invasion and takeover of the cockpit by the terrorists frees it from liability. The plaintiffs said Boeing should have designed its cockpit door to prevent hijackers from invading.

In addition, they had said that American and United airlines and the Port Authority were legally responsible to protect people on the ground when the hijacked aircraft smashed into the twin towers, causing them to collapse.

As a result of the ruling, court officials were preparing for a possible legal onslaught at the Manhattan courthouse as early as this week as some people choose lawsuits over applying to the federal victims’ compensation fund.

The last day families can apply for compensation is 22 December. The fund was created by Congress to provide financial aid to the families of those killed or injured in the attacks, and to protect the aviation industry from crippling litigation.

As of late August, 2,275 claims had been filed. However, about 1,700 families had yet to decide whether to enrol with the fund or join lawsuits against the airlines, security companies and government agencies. The average pay-out so far has been $1.5 million.