Dozens of Scottish companies have revealed their gender pay gaps, with some paying men almost twice as much as women on average.

Two investment firms, a private school, an oil company and a tanning bed chain have reported the largest differences.

They include Edinburgh-based Franklin Templeton Investment Management, which has admitted paying female staff 46% less on average.

It is among around 100 companies registered in Scotland which have published their pay divides two weeks before the April 4 deadline, including STV.

Dr Suzanne Doyle-Morris, a gender balance expert from the InclusIQ Institute in Edinburgh, said: "Highlighting the pay gap is valuable for three reasons.

"It helps companies identify good and bad practice, it's a really good message to send to employees, and it will help diminish discrimination and bias," she said.

Dr Doyle-Morris said many women earn less than men from their first post-university job onwards.

"The research shows that in your first job post-university there's a gender pay gap. It starts that early on.

"HR and marketing tend not to be so well paid and not surprisingly they tend to have more women in those roles.

"If we had more men in HR I'm certain the pay and respect for the job would increase."

Other prominent Scottish companies which have reported their pay gaps include the Royal Bank of Scotland (36.5%), Clydesdale Bank (36%), Lloyds Banking Group (32.8%), Scottish Power Energy Retail (30.5%), Wood Group (23.1%), Diageo (16.7%) and BrewDog (2.8%).

Media companies which have stepped forward include STV (17.3%), Herald owner Newsquest Herald and Times (17%) and Daily Record owner Scottish Daily Record and Sunday Mail (15.5%).

Twenty-four companies have reported no gender pay gap or a divide in favour of women.

The gender pay gap is the difference between the average hourly earnings of men and women.

It is different from equal pay as it has been illegal to pay men and women differently for doing the same job since 1970.

A gap is often the result of men occupying most of the top jobs at an organisation.

We have used the median average because it is not as affected by extreme values like the high earnings of a small number of people at the top of an organisation. This method is also favoured by the Office for National Statistics.

However, because high-earners are predominantly male, the mean is an important measure of women's experiences in the labour market. It also makes international comparisons easier.