British television and radio broadcasters remain “woeful” at promoting staff from diverse backgrounds to senior management positions, according to the media regulator Ofcom.

While the media workforce had become more representative of the wider country in recent years – owing to substantially increased recruitment of people of colour and disabled staff for junior jobs – this had yet to replicated at executive level, it said.

As a result, the individuals who ultimately decide what appears on British television and radio outlets do not reflect the social make-up of either the staff they manage, or the country at large.

“Broadcasters appear to have focused on entry-level recruitment at the expense of retaining diverse staff and enabling them to progress,” concluded Ofcom.

The regulator said many people drifted out of the media industry because they were not supported to make the step up to management jobs. “There is a woeful lack of diversity within senior positions and key decision makers,” it concluded.

Vikki Cook, Ofcom’s director of broadcasting policy, said: “Broadcasters have made progress hiring a wider range of talent. For example, there are twice as many people working in radio from minority-ethnic backgrounds as there were three years ago.

“But for the first time, more people are leaving the industry than joining, particularly women, while disabled people remain significantly underrepresented. And because companies have focused on entry-level recruitment, there still isn’t enough diverse talent in senior roles. So, we’re calling on broadcasters to slow the revolving door and focus on retaining and progressing talented people from all walks of life.”

Marcus Ryder, a former BBC journalist who now works with Birmingham City University’s Sir Lenny Henry Centre for Media Diversity, has long argued that staff retention is one of the biggest issues affecting the media.

He said too many staff from minority backgrounds leave the industry because of a lack of career progression or a belief that the culture is unwelcoming.

While 15% of BBC staff come from minority-ethnic backgrounds – higher than the general population – this falls to 9% among senior managers.

“There is a growing demand for Ofcom to regulate diversity in the same way it regulates regional diversity: with strong licence requirements and enforceable minimum standards,” Ryder said.

“In private conversations Ofcom says it does not have the powers to do this. Yet in the past Ofcom has publicly called for the government to give them more powers when they do not think their existing powers are up to the task.

“I think it is time they either exercised their existing powers with more force or asked the government for more powers. Quietly nudging the industry does not seem to be a policy that has yielded significant results.”

The research data has also found the BBC is the only one of the UK’s major television broadcasters where the majority of staff stated they do not believe in any faith, while staff at Channel 4 were the most likely to consider themselves religious.

However, one area of diversity in the media that Ofcom has struggled to monitor is social class and family wealth, which is not considered a protected characteristic under equalities legislation. The regulator said it had only a partial view of the issue because many companies were unsure how to judge the backgrounds of their employees.