Companies with the most women are the best performers, which is worrying for the IT sector, according to the president of trade association Intellect.

And the gender imbalance is an increasingly serious issue amid the IT skills shortage, he said.

"With over 140,000 new entrants needed every year, the gender imbalance in those taking computer science related degrees and in the technology sector in the UK is one of the worst in Western Europe," said Finnan in his president's report.

"In 2007, only 18 per cent of IT and Telecoms professionals were female. This number is particularly worrying when numerous reports show that companies with the highest proportion of women in senior management experience better financial performance for both return on equity and total return to shareholders."

A 2007 report by management consultancy McKinsey and Company found that return on equity was 35.1 per cent higher in companies with the highest proportion of female senior managers.

And female chief executives and board directors add 10 per cent to capital return, according to research by the University of Helsinki.