Just six per cent of those training for a career in cyber security are female, according to figures published by QA, the UK's largest IT training company.
The proportion of women working in Britain's IT and telecommunications industry stands at just 18 per cent, meaning that women represent under one in five of the sector's workforce, but among those seeking a cyber security role this ratio drops even lower, with just one in every 20 trainees being female.
QA's figure comes from the number of men and women enrolling for its courses. In total, 2,500 people trained in cyber security but just 150 of these were women. The figure represents a 20 per cent drop in the number women studying cyber security during the previous year, in stark contrast to the number of men training in the field, with that figure more than doubling between 2011 and 2012.
"It's unclear why women are so under-represented in such an important and fast-growing part of Britain's IT economy," said Bill Walker, technical director for QA.
"Various theories abound - from gender stereotyping to teaching the wrong kind of technology, such as office IT instead of more relevant computer science skills."
Earlier this year, the National Audit Office (NAO) warned that the UK is desperately short of the skills required to protect against cyber threats and more cyber security experts need to be trained.
"Despite the huge rise in men taking cyber security training over the past year, Britain is still falling short of the number of people needed to plug the skills gap identified by the NAO," Walker added.
"It needs to be easier, more affordable and more appealing to women, in order for them to enter this vital segment of the IT economy."