Brian O'Hara and Gavin Arton could not believe their eyes as they saw plumes of smoke billowing from the World Trade Center.

And then XL Capital Ltd.'s chief executive officer and senior vice president could only gasp when they saw a second explosion and saw a ball of flames burst from the buildings as they headed across the river to Manhattan.

"We were literally driving over the George Washington Bridge and I looked out of the window, and I said to Brian O'Hara: `It looks like the World Trade Center is on fire.'

"And then there was this explosion, and we thought it was the same building because we didn't see the plane and from our angle you couldn't tell.

"We saw the fireball, and that must have been the bigger plane hitting," said Mr. Arton, who has been stranded in the US with Mr. O'Hara.

"We turned on the radio and that is when we heard what was happening."

The men were in New York for a day trip and heading for a meeting in the financial district when they saw the attack.

"Obviously everything we were involved in that day was cancelled."

The men joined with the XL team in the US and set about checking that all their staff and their families were safe.

"It was like a chain. Thankfully, as far as we know, everyone was accounted for."

Mr. Arton said the panic was compounded because nobody could get an outside line. Luckily he had slipped his cell phone in his pocket, more from habit than from need and was able to call his wife to allay her fears.

He said: "Not long ago I was in Windows on The World at 8 a.m. With meetings, people could be anywhere."

He added: "It is the not knowing that really causes people to panic."

And while he has heard no bad news about XL workers and their families, he has found out about several friends who perished in the attack, and is mourning their loss.

"It is a terrible tragedy of a scale we cannot comprehend," he said.

"At least we were safe. At least nobody in our organisation, to our knowledge, was involved.

"You can feel it here, you feel it physically, the scale of the disaster.

"I was in the city and there was a girl terribly distraught, and she was being comforted by her mother.

"She may have lost a boyfriend. It is everywhere here.

"It is the quietest I have ever seen New York. There was not an aeroplane in the sky, the only thing you could hear were sirens.

"There were people walking down the centre of the streets."

Mr. Arton moved to the XL offices in Connecticut and has been conducting business from these offices.

"You look along the Long Island Sound and there are patrols out there.

"We are still on military high alert.

"It is not scary. There are no planes.

"But you hear a noise and you look up, and a jet has just gone by."