Male managers are blocking efforts to improve the gender balance at UK companies, according to research by the Chartered Management Institute, raising fresh concerns about entrenched sexist views in the workplace.

A study of 1,149 managers across the UK found that there was passive, and even active, resistance to gender equality from male bosses in many companies. The survey discovered that two-thirds of male managers believed their organisation could successfully manage future challenges without gender-balanced leadership, whilst a third of male managers felt too much effort was focused on ensuring gender balance in the workplace (compared with 13% of female managers).

Ann Francke, chief executive of the CMI, said that the “concerning findings suggest that the prospect of us regressing is ever-present”. The data has picked out “resistance and perhaps even early signs of backlash among many men”, she added.

The survey follows widespread condemnation of sexist remarks directed at Aviva chief executive Amanda Blanc at the company’s AGM last week. Blanc said that overtly sexist behavior had increased, despite efforts by campaigners to improve gender balance in the workplace.

Dame Inga Beale, former head of Lloyd’s of London insurance market, said the episode demonstrated that the drive for gender equality still had “some way to go”. “My outspoken approach has cost me in certain situations, as being seen as too much of a challenger in this regard can impact your career, and this is a classic example of why we still need to tackle sexism in the workplace,” she told the Financial Times, adding that her advocacy on the topic had affected her applications for non-executive director jobs.

Beale, who attempted to improve the culture at Lloyd’s in her five-year tenure – a market where she has previously said junior female underwriters would be called “box bunnies” and “box bitches” – called for a “concerted effort from all to bring about equality in the world of business”.

The CMI said that there was still a wide gap between male and female managers’ views on the need for more gender-balanced leadership, with an “active pushback” among male managers.

Francke said gender diversity was vital for future economic growth and social progress. She added:

“Sexist remarks directed at Amanda Blanc at [Aviva's] AGM are just this week’s highly public example of the inequalities that exist at every level of organisations. There has been too little effort devoted to communicating the enormous benefits that greater equity offers, including for better business and organisational performance as all talent is better developed and deployed.”

The CMI survey also reported opportunity differences between female and male managers with children. About 37% of female managers with children felt they had been overlooked for promotion, compared with 27% for male managers, with about a third saying that they had missed out on a salary rise.