The BBC is failing older women and minorities by focusing on the “middle-aged and middle-class” according to the boss of Ofcom, citing new audience research from the regulator.

Sharon White said there should be “tougher, stronger” regulation to ensure the BBC and other broadcasters reflect the diversity of the UK, and did not rule out imposing quotas to achieve that goal.

The BBC has set ambitious diversity targets for on- and off-screen staff, which it says it is on track to meet. However, the corporation and other broadcasters have repeatedly been criticised for slow progress, and in particular a failure to tell a diverse range of stories about minorities. On Tuesday, actor and writer Meera Syal described BBC drama Three Girls, about the Rochdale abuse scandal, as an example of the failure to treat Asians as “people, not issues”.

Speaking just weeks before Ofcom takes over regulation of the BBC, White told the Oxford Media Convention the corporation must lead on diversity: “Too many older people, especially women, feel they’re negatively portrayed on TV … People from a minority group – whether a distinct region of the country or a particular ethnicity – feel that they are neutrally portrayed at best, or negatively at worst. These are challenges the whole industry can – and must – address.”

She also said the BBC remained much loved and trusted but was in danger of resting on “nostalgia” rather than its current output and needed to do more to attract younger audiences. She said Ofcom’s audience research had found that “younger groups often saw a lack of risk-taking. The BBC was not offering enough edgy content, or services relevant to them.

“Many people we spoke to felt the BBC was overly focused on middle-aged, middle-class audiences. They said it could do more for the wider public, ethnic minorities and younger groups.”

Ofcom’s new responsibilities include ensuring that the BBC’s output is “distinctive” from its commercial rivals, with some suggestions that the corporation should not broadcast mass-entertainment shows such as The Voice, which was poached by ITV in 2015.

Ofcom is in the final stages of preparing a framework to assess the BBC’s performance, including its distinctiveness, which White said would involve extensive consultation with the public.

However, she said aiming for greater distinctiveness should not stop the BBC from trying to be popular. “Some worry that a more distinctive BBC must be a less popular broadcaster. I disagree,” she said. “Many of the BBC’s most-loved programmes – EastEnders, Match of the Day or its radio breakfast shows – are distinctive and original in their own way.”

White said the BBC needed greater transparency over complaints, which Ofcom would also oversee, saying that “audiences must feel protected”.

“We won’t hesitate to intervene if we have concerns. And we’ll oversee how the BBC handles its own complaints, to make sure people are treated fairly. I personally am also very keen to see the BBC resume publishing its complaint numbers, which is good for transparency,” she said.

She added: “We recognise the BBC clearly has special status, but we will give it no special treatment.”

Asked whether she felt regulation could help tackle fake news and other problematic content on social media, she said she wanted companies such as Facebook to take “much more responsibility”. She said: “The responsibility in the first instance rests with those companies. I am nervous about regulation because I think there is a real question about where the appropriate boundary is. But I feel absolutely very strongly the companies must do more.”

A BBC spokesperson said: “As Sharon White said, there are challenges facing the whole industry and while the BBC has already made significant progress in reflecting the full diversity of today’s UK on and off air, we’ve set out plans to do even more.”