JUST seven of Scotland's top 30 listed companies has a female executive, The Herald can reveal, although the number of non-executive directors has soared in the past year.

Companies including Glasgow-based temporary power giant Aggreko, oil services company Wood Group, sausage skin maker Devro and broadcaster STV, which a year ago had no female directors, have appointed women to their boards. In all, eight Scottish companies added to their cadre of female directors.

Figures compiled by The Herald show that 37 out of 242 board positions, both executive and non-executive, in the top 30 companies are occupied by women.

This is a 27.6% increase in the last year but still leaves 84.7% of seats filled by men.

Helena Morrissey, chief executive of fund manager Newton Investment Management and co-founder of the 30 Per Cent campaign that seeks more women on boards, said: "I feel that we are on the cusp of quite a big breakthrough."

She said the next major challenge is ensuring women obtain executive positions, although this is a much greater task.

"To be a successful non-executive director you can have a range of skills," she said.

"To be a successful CFO [chief financial officer] you have to have particular skills and you cannot develop a CFO overnight."

The only female chief executive at one of Scotland's top companies is Katherine Garrett-Cox of Dundee investment giant Alliance Trust.

There are just seven companies with female executives such as Louisa Burdett, finance director of Fife-based optical imaging firm Optos, who replaced another woman, Christine Soden, earlier this year.

Others include Sarah Haran, director of cloud computing firm Iomart; Daine Fraser, finance director of Melrose Resources; Jann Brown, finance director of Cairn Energy; Anne Richards, chief investment officer at Aberdeen Asset Management; and Standard Life finance director Jackie Hunt.

Niki Kandirikirira, executive director of Edinburgh-based campaign group Engender, said having more female board members doesn't necessarily lead to change in the workplace.

"People assume there will be some kind of trickle tickle down," she said.

"We are more concerned about having workplaces that allow women to work flexibly and disable the discriminatory ideas that women are going to take time off and are therefore not worthy of investment."

One notable exception to the trend of increased female board representation is Aberdeen-based transport company FirstGroup which has no women on its board after losing non-executive Audrey Baxter in December.

Two subsequent non-executive appointments have both been men.

A spokesman said: "We support the call to raise the proportion of women on UK boards and we have set an ambition for 20% of our board positions to be filled by women by 2015.

"We continually review board composition to ensure that we have the right mix of capability and experience."

It said one-third of members of its executive management board are women.

A hard-core of Scottish companies remain women-free zones, including Wolfson Microelectronics, internet dating company Cupid, Irn Bru maker AG Barr, packaging specialist British Polythene Industries and Scottish Investment Trust.

A spokesman for AG Barr said: "We seek always to have the optimum board composition and capability with a diversity of skillsets and viewpoints. We review its composition and effectiveness regularly."

Steven Hay, company secretary at Scottish Investment Trust, said it had not made any board appointments in the last year.

"If and when there is a refreshing of the board it will be the best person for the job that is required."

He said half of trust employees are women.

The others did not respond to a request for comment. Recent listed companies, oil explorer Parkmead and energy meter specialist Smart Metering Systems, also have no women on their boards. Neither provided a comment.