The former Minister for Women and Equality was the key architect of the Equality Act 2000, which introduced a requirement to report gender pay gaps.

“We should not be discussing it anymore – we should be setting targets to close [the gap],” she continued. “Year on year, we need to see progress and we need to have stretching targets – these gaps are not there for us to be gnashing our teeth at or for admiring those that have lower gaps, they are there for us to make progress towards equal pay.”

Harman raised the 89% bonus gap between men and women at the bank, JP Morgan, as an example of the extreme discrimination that exists in UK business. “You shouldn’t dignify that with a discussion,” she said.

Some 10,000 companies, employing more than 250 staff, were required – for the first time – to report their gender pay gaps by 4 April (30 March for public bodies) this year. The pay gap is the difference between the average hourly earnings of men and women, reported as both a mean and a median average. Bonus payments are also covered by the legislation.

Harman was sitting on a panel at the RTS early evening event in mid-April that also included BBC current affairs journalist Jane Corbin. “I was shocked to see the Channel 4 pay gap of nearly 30%, that from an organisation that’s fond of telling us about its credentials on equality and diversity,” she said.

Channel 4 recorded the worst (mean) average pay gap of 28.6% of the major UK broadcasters, followed by: UKTV, 17.9%; ITV, 16.4%; the BBC, 10.7%; Sky: 5.2%; and Channel 5, where women are, in fact, paid 2.9% more than men.

TV is performing no worse than other UK businesses – but also no better. Analysis by industry magazine Broadcast of the figures provided by 15 broadcasters and producers revealed an average pay gap of 14.8%, which almost mirrors the 14.5% national average.

Gender pay gaps in television, equality adviser Charlotte Sweeney told the RTS event, “are not as bad as I’ve seen in many sectors”.

Nevertheless, there are many examples in television of huge pay gaps. Jane Corbin’s report for BBC One’s Panorama in March revealed that Martina Navratilova was paid 10 times less by the BBC than fellow ex-player John McEnroe to commentate at the Wimbledon tennis tournament.

Former RTS chief executive and current chair of the Campaign for Broadcasting Equality, Simon Albury, who was in the audience, noted that BBC Director-General Tony Hall claimed that closing the gender pay gap had been a “personal priority over the last four years”. Why, Albury asked, if this is the case, has “nothing happened”?

“Because it was a ‘priority’ with a really microscopic ‘p’,” replied Harriet Harman. “You can’t be that ineffectual if you’re at the top of the BBC.

“Everybody’s been paying lip service. The point about these [pay gap] numbers now is that ‘the lip service’ has been exposed.”

Sian Kevill, the founder of factual indie Make Productions, as well as a former director of BBC World News and editor of Newsnight, recalled that when Hall became Director-General in 2013, “he almost imposed Mishal Husain on [Radio 4’s] Today programme to [put] another female voice on that very male-dominate programme.

“There’s a mentality that maybe [if] you make one change like that, somehow the trickle down [effect] will send a flood through the whole organisation – the [pay gap] figures have now shown that that doesn’t work. You can make a totemic change like [bringing in Husain], but it didn’t have any broader effect within the organisation. It needed more systemic change and [Hall] hasn’t done that.”

Kevill also called for TV companies to carry out “transparent pay audits”. She added: “There shouldn’t be a let out for any company – let’s say in five years’ time, there shouldn’t be a gap.

Corbin warned, however, that in TV, “where there isn’t any money, it is going to cost to make sure these [pay] imbalances don’t happen. [Not all] men are going to be taking pay cuts – it’s not going to happen. So, the money has to be found and that’s very difficult, particularly for the BBC and Channel 4.”

The early evening event, “Mind the gap: closing the gender pay gap in television”, was held at the Hospital Club, central London on 16 April. It was chaired by media journalist Jane Martinson, and produced by Martin Stott and Vicky Fairclough.