More than 50% of independent directors at the top 150 UK public companies were women in April, compared with just 18% a decade ago, according to recruitment firm Spencer Stuart Inc. Women occupy over a third of board seats overall – in line with UK government targets – though 50 companies missed that benchmark.

UK public companies are being pushed improve on gender diversity. Larger firms are 10 times more profitable on average if they have one-third female executive boards than if the boards are all male, diversity consultancy The Pipeline said in a study last year.

Performance on ethnic diversity was markedly worse, with 39% of firms having no minority directors at all. People of colour held about 11% of board seats.

The data shows that the gender improvement is still not being reflected at the top level, with women accounting for just 8% of chief executive officers and 9% of chairpersons.