The Duchess of York said the service was inspirational

On the day of the attacks, she had been due to visit her charity, Children in Crisis, which had an office on floor 101 of the center's north tower, provided by Cantor Fitzgerald.

She said the service had provided words of inspiration for those affected to help them keep going through their grief.

"It was a wonderful service, full of inspiration for everyone to fight on for the future."

Scars of terrorism

The service was introduced by the Dean of St Paul's Cathedral, the Very Reverend Dr John Moses.

He said it was to remember all who died in the 11 September attacks.

Nigel Thompson, one of the hundreds of Cantor Fitzgerald employees lost

"We recall especially all colleagues in Cantor Fitzgerald who lost their lives as they went about their work in the World Trade Center.

"We pray for them, for their families and friends and we remember also all who were injured and who bear the scars of terrorism."

The congregation sang several hymns including Amazing Grace and the American traditional Battle Hymn.

President and Chief Executive of Cantor Fitzgerald, Lee Amaitis, also gave a reading.

Cantor Fitzgerald spokeswoman Cara Kiewel said: "I think it probably affected everyone in a slightly different way.

"Some people were mourning the loss of close friends and relatives, and others who had a connection with the company just wanted to pay tribute."

Cut off

A goliath of the financial world, Cantor Fitzgerald handled $50,000bn of business last year.

Acting as an exchange for the world's bond markets, it has operations in the City of London and New York city.

The company had 1,000 staff working on floors 101-05 of the North Tower of the World Trade Center, close to the point where the first plane hit.

When the first plane struck, its employees were cut off with little chance of escape.

None of the firm's staff at work that morning are believed to have survived.