All staff, including comms personnel at the department, were audited to arrive at the figures, which compare with a national gender pay gap of 18.1 per cent.
The campaign to educate businesses and organisations about their responsibilities under the new regulations is being led by the Government Equalities Office (GEO), which sits within the Department for Education.
The department assessed the wages and bonuses of its 5,400 employees to arrive at its mean and median pay gap figures.
But it also assessed pay by quartile of seniority and found that 55 per cent of the senior civil servants were female and that there was a higher proportion of women than men in its top pay quartile.
However, there was also a higher concentration of women to men in the department’s lowest pay quartile, which has contributed to the gender pay gap.
The department also looked at bonus pay and found that the mean gender pay gap for bonuses was 0.8 per cent.
Government regulations that require companies with more than 250 staff to begin reporting their gender pay gap came into force in April.
The regulations affect 9,000 employers in the private, public and voluntary sectors – some 15 million workers across the UK – who will be required to publish their figures by April 2018.
Affected companies and organisations will have to publish annual figures on the median and mean gender pay gaps in their organisations, looking at low, medium and high earners to arrive at the figures.
They will also be required to publish the proportion of men and women in each quartile of the pay structure, as well as the gender pay gap for any bonuses paid out during the year.
The agency will help the GEO's in-house comms team add "scale and pace" to its own efforts to reach employers during the first year of the regulations coming into effect and Portland’s job will be to help raise awareness of the new regulations by targeting those businesses and organisations that the GEO's research has identified as being hardest to reach.
Commenting on the publication of the department’s figures, Justine Greening, Secretary of State for Education and Minister for Women and Equalities, said: "I'm proud that the Department for Education has taken an important step in reporting its gender pay gap, setting an example to other employers as we build a stronger economy where success is defined by talent, not gender or circumstance...
"As one of the UK's largest employers, the public sector has a vital role to play in leading the way to tackle the gender pay gap which is why the DfE’s step to publish our gender pay gap matters.
"Through transparency we can find out what the situation is, where there is best practice and create pressure for more progress."
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