The watchdog which oversees MPs’ behaviour must have more freedom to investigate historic abuse allegations, Parliament’s committee on standards has urged.

Following a major investigation by Dame Laura Cox into “pervasive abuse” in Westminster earlier this year, the committee said the parliamentary commissioner for standards, Kathryn Stone, must be given more independence to investigate politicians.

The committee – which blocked a probe into John Bercow in May – called for rules which mean the commissioner must consult MPs before launching a historic investigation to be abolished, calling it an “unacceptable encroachment” into her independence.

Similar rules about needing to seek advice before probing a former MP must also be scrapped, the committee said.

Meanwhile, following recommendations from the Cox report that MPs should be completely excluded from determining whether their Commons colleagues harassed or bullied workers in Westminster, the committee called for its lay members to be given full voting rights.

Under current rules, lay members – who make up 50% of the 14 person committee – are only able to cast ‘indicative’ votes.

Earlier this year, the committee voted three-two against allowing the commissioner to investigate claims that Bercow bullied staff – allegations he emphatically denied.

The then-chair, Labour MP Sir Kevin Barron, said lay members should have voting rights.

The latest report also acknowledged the committee has “deeply regrets what has gone wrong” over bullying and harassment in the House of Commons, adding: ”(We) commit ourselves to contributing to putting things right.”

Cox’s report into bullying and sexual harassment in Parliament, which was published in October, called for sweeping reforms after an investigation revealed a culture of” deference, subservience, acquiescence and silence”.

Allegations of sexual harassment in the report included “frequent and inappropriate touching”, men patting women’s heads and putting their arms around women, leaving a hand on their knee “for an uncomfortably long time”.

Other examples included men attempting to kiss women, and grabbing or stroking their arms or bottoms or breasts.

Labour MP Kate Green, who chairs the standards committee, said it was “vital” to rebuild trust in the complaints process following Cox’s investigation. 

“Whilst there is clearly much more to be done, our recommendations will make an important step forward towards a fairer, more independent and credible system,” she said. 

“The standards committee is unique in having an equal number of MPs and lay members on it, and these proposals will ensure that the skills and expertise of the lay members can help to hold MPs to account in the most effective way.”