Gender diversity has improved more on company boards around the world where the chief executive or chairman is also a woman, according to research from Deloitte.

The firm’s latest Women in the Boardroom report reveals that diversity has risen, with 15% of board seats globally now held by women—a rise on 12% in 2015.

But the report found that women held 29% of board roles where the chief executive is also female. Where boards were led by men, the figure is 15%.

Nick Owen, chairman of Deloitte North West Europe, said: “Globally, organisations with women in the top leadership positions have doubled the number of women holding board seats. As the number of female CEOs and board chairs climbs, it is likely to spur greater board diversity and build a culture of inclusion.”

Norway tops the gender diversity rankings with 42% of boardroom seats occupied by women, followed by France with 33%. The UK lags behind on 20% but has improved on the 15.6% of two years ago.

In the period from 2015, New Zealand saw the greatest improvement with female boardroom representation rising from 18% to 28%.

Owen said: “The increase in the number of women on UK boards and the fact that many companies have met or exceeded Lord Davies’ target is positive. The focus is now on the representation of senior women below the board level.

“The Hampton-Alexander review recommended that women should hold one-third of positions on, or reporting into, executives committees at FTSE 100 companies. Although achieving this will be difficult, more diverse management teams will have a real impact on building an inclusive culture, underpinned by respect.”

He added: “As organisations navigate technological and societal shifts which are transforming the future of work, boards will have a critical role to play. Diversity of thought and people will be critical to ensure that board members are exploring challenges from every angle and consistently bringing a fresh point of view.”