Larger companies are narrowing the gap with SMEs in terms of the number of companies that have a female director, according to new research from Experian's BusinessIQ.

The study looked at 2.7m UK businesses between 2007 and 2012 and found that the overall number of directors has risen to 5m in 2012 compared to 4.3m in 2007 - the uplift in female directors had outstripped men: 24% compared to 15%.

Taking into account business failures and new start-ups during the period, as well as changes to directorships of surviving businesses, 240,000 more female directors have been appointed.

While small companies (3-10 employees) are still more likely than large companies (250+ employees) to have female directors, the gap between the two is narrowing. In 2007, 48% of small companies had at least one female director compared to 33% of large companies. In 2012, half (50%) of small companies had female directors compared to 40% of large companies.

Start-up businesses played a key role in bolstering the number of female directors employed over the period. A third of the 1.4m businesses that started up since 2007 have one or more female directors, adding 523,000 female directors overall, replacing the 297,000 female directors whose companies closed between 2007 and 2012.

Despite the rise, Experian found little change in the types of profession dominated by females. In 2007, hairdressing, primary education and social work were the industries with the biggest percentage of all female boards and this trend has increased further according to data for 2012.

At the other end of the scale, over the five year period there were fewer all-female boards in 2012 in some typically male-dominated professions such as plumbing, installation of electricity and software publishing.

Max Firth, UK managing director for Experian's Business Information Services division, said: 'Smaller companies are clearly the driving force for female directors, but our research shows that larger companies' efforts to increase the number of female directors has made a significant difference over the past five years.

'And let's not forget the contribution made by female entrepreneurs, with many starting up their own companies to manage work/life balance and fit with family commitments, without whom the number of female directors would be considerably lower.'

Meanwhile, a separate survey from recruitment company Randstad, found that just 43% of full-time accountants are women.

Of the 70,000 full time chartered accountants employed full-time in the UK in 2011 just 30,000 were female. The accountancy profession lags behind the law fraternity where 50% of full time professionals are women.

Accountancy compared favourably, however, to managers in financial institutions, actuaries, economists, and statisticians where just 35% of full time staff are women.