MPs’ letter criticises on-air ban for presenters who have expressed opinion and says government should ‘set the tone’ for employers across UK

More than 70 MPs have called for the culture secretary, Matthew Hancock, to force the BBC to allow female staff who have campaigned about equal pay to talk about the issue on air.

A letter signed by the group of MPs warns Hancock that preventing discussion could have a “chilling effect”. It urges the government to use powers in the royal charter to “give a direction to the BBC to ensure the freedom of speech of staff in pursuit of equality of opportunity”; this would provide clarity about how the government expects organisations to respond to equal pay claims, the MPs say.

The issue of BBC pay was dragged back into the open last week when Carrie Gracie resigned as China editor and accused the broadcaster of a “secretive and illegal” pay culture.

The BBC faced accusations of censorship when prominent female broadcasters, such as Radio 4’s Jane Garvey and Winifred Robinson, were told they could not report on the equal pay row if they had publicly expressed support for Gracie or a campaign for equal pay at the broadcaster.

The letter to Hancock was orchestrated by the Labour MP Stella Creasy and is signed by another 72 MPs from Labour, the Liberal Democrats, the SNP and Plaid Cymru.

It says: “These reports that members of staff at the organisation have been told that they cannot comment on these matters in public without this affecting their duties directly impacts on their capacity to be able to seek equal pay.

“Freedom of speech is vital to tackling these often difficult and sensitive issues – the debate over the BBC’s handling of this situation will set the tone for employers across the country in how they respond to equal pay claims.

“Without action to protect the right of all staff to discuss this matter, their conduct could have a chilling effect on both the employment rights of staff at the BBC as well as wider public perceptions about the appropriate conduct of employers in responding to the law on equal pay.”

The MPs say Hancock has the power to intervene in the issue through the BBC’s royal charter – the agreement that protects its independence, defines its public responsibilities and sets the licence fee it receives.

The Equalities and Human Rights Commission has already said it will write to the BBC to seek answers about allegations of pay discrimination, but the MPs claim the government has cut funding to the organisation and left it “under-resourced and grossly underfunded”.

Creasy said the BBC’s response to the pay row “could well influence how many other employers respond too”. She told the Guardian: “That’s why we’re asking the secretary of state to turn words into deeds and use his direct powers to ensure that men and women within the corporation can express their views on this equally and defend their right to free speech in the workplace.”

Hancock told ITV’s Peston on Sunday that “we have got to have equal pay for equal jobs” and that the BBC “has a special responsibility to lead and to be a beacon because this issue is broader than the BBC”.

In a statement, the DCMS said: “It is clearly important that the BBC remains operationally and editorially independent from government. However the secretary of state has been very clear that the BBC must be a beacon for the British values of fairness that this nation holds dear.

“That includes fair pay and equal pay for equal jobs – it’s not just about levelling women’s pay up but reasonable pay at all levels. The BBC must act, because the brilliant women working at all levels of the BBC deserve better.”

A spokesperson for the BBC said: “We will be publishing a report and setting out a range of further actions shortly. People should see that work and action before judging our approach.

“Meanwhile we will continue to report the story across our airwaves. Whilst we’re always mindful that presenters and correspondents need to be aware of our impartiality rules, no other media organisation would have covered a story about itself in such great depth.”