For the third Friday in a row, journalists working for Spain’s public broadcaster have worn black on screen to protest against alleged political interference, gender bias and unequal pay.

The campaign, known as viernes negro (black Friday), is intended to highlight the Spanish government’s continuing refusal to approve a transparent process to appoint an independent board at RTVE.

Protesters argue that the ruling conservative People’s party (PP) meddles in media coverage and has a vested interest in appointing the RTVE chair directly.

“For the third consecutive week, RTVE workers are wearing black this Friday to protest against the parliamentary impasse that is hindering the establishment of a public competition to choose the leadership team and restore RTVE’s professional judgment,” the group RTVE Women said in a statement.

“This struggle, which aims to get RTVE offering diverse, quality and independent information, is one that concerns all of us – including the average citizen whose taxes pay for the production and distribution of RTVE content.”

Journalists have been using the hashtag #AsiSeManipula(#ThisIsHowTheyManipulate) to share their experiences of bias and the pressure placed on them to report certain stories in certain ways.

On Tuesday, an RTVE editor resigned after her TV channel failed to run a video in which a government aide was caught criticising protesting pensioners. The aide said: “How I’d love to give them the finger and tell them to go fuck themselves.”

The broadcaster also made headlines in November after it used the theme music from the horror film The Exorcist to accompany a clip featuring the deposed Catalan president Carles Puigdemont.

Six years ago, a number of RTVE journalists were allegedly purged from the broadcaster for questioning PP’s austerity measures. RTVE’s current chair, José Antonio Sánchez, has been accused of pro-PP bias.

RTVE Women has called on the public to join the campaign by posting photos of themselves dressed in black under the hashtag #BlackFriday3. It also urging people to use the hashtag #Don’tChangeChannel, in response to the Spanish finance minister’s recent suggestion that people could simply switch channels if they didn’t like RTVE’s coverage.

Campaigners are hoping to harness the momentum generated by Spain’s recent “feminist strike”, in which about 5 million women participated, and the public outcry over a court’s decision to clear five men of the gang-rape of a teenager. Male journalists are also backing the cause.

“We suffer the consequences of sexism – the glass ceiling; the pay gap – and we’re not prepared to keep working under unequal conditions,” RTVE Women said. “It’s about justice and we’re convinced that, when it comes to a job that needs to be socially responsible, our view offers a less partial view of reality.”

RTVE said it would not comment on the campaign or accusations of bias.