The powerful City figure was awarded the honour for her career in the financial services industry but she refused to speak to the press following the Buckingham Palace ceremony.

Dame Clara's tenure of the Stock Exchange has faced criticisms in recent weeks after a computer crash paralysed the index during a day's trading.

The problem on September 8 came on a day which should have been one of the busiest of the year but the market was stopped for seven hours – the longest delay in more than eight years.

The stoppage meant investors were unable to cash in on a worldwide stock market boom triggered by the US Government's bail out of mortgage giants Fannie Mae and Freddie Mac.

Before the investiture ceremony, Dame Clara lined up with other recipients outside the palace's ballroom. A few minutes later she emerged, clutching in a presentation box the damehood insignia she had received from the Queen but did not speak to waiting press.

In 2001 she became the London Stock Exchange's first female chief executive.

Dame Clara was born to Dutch parents in Canada in 1957 and after studying at the London School of Economics began her career in the City in 1979.

The chief executive became a commodity broker at Phillips and Drew in 1983, moving on to become its director five years later. Her career progressed quickly and she held a number of senior posts in the City.