Spain’s deputy prime minister, Yolanda Díaz, has apologised for her party’s delay in dealing with a senior MP who resigned last week amid multiple sexual assault allegations.

In a scandal that has rocked Spanish Left-wing politics, Íñigo Errejón, spokesman for Ms Díaz’s hard-Left Sumar formation, was accused by actress and TV presenter Elisa Mouliaá of sexual aggression and harassment.

Mouliaá‘s complaint followed claims made online by over a dozen anonymous women that the 40-year-old was a serial perpetrator of “psychological abuse”, “gaslighting” and “humiliating sex practices”.

Mr Errejón, who was tipped as the next Sumar leader, resigned last Thursday hours before the party’s leadership moved to strip him of his post.

Spanish police confirmed on Friday they had opened an investigation into the case.

Ms Díaz admitted that her party had been “late” in uncovering Mr Errejón’s behaviour while attempting to scotch claims there had been a cover-up.

“As feminism has shown over recent days, there will be no impunity – no matter who it is, what it’s called and who has to fall,” she said after a meeting with MPs on Monday afternoon.

“If I’d known early about such serious acts earlier, I would have acted in exactly the same way,” Ms Díaz said.