Senior Tories have rallied around Boris Johnson’s aide Munira Mirza after the Prime Minister was accused of waging a “culture war” by allowing her to play a major role in setting up his commission on racial disparity.

Ms Mirza, the head of the No 10 policy unit, has previously questioned the existence of institutional racism and hit out at a “culture of grievance” among anti-racism campaigners.

Her involvement in establishing the body was condemned by shadow justice secretary David Lammy, who claimed her role undermined the commission.

The Prime Minister announced the Commission on Race and Ethnic Disparities after a series of anti-racism protests on British streets triggered by the death in the US of George Floyd while in police custody.

Mr Lammy previously led a review of the treatment of black, Asian and minority ethnic (BAME) groups in the justice system for the Tory government under David Cameron and Theresa May.

He said: “My review was welcomed by all parties: (Jeremy) Corbyn, Cameron and May.

“But Munira Mirza went out of her way to attack it.”

Mr Lammy accused the Prime Minister of not listening to the Black Lives Matter campaign, and instead claimed “he’s trying to wage a culture war”.

Labour MP Zarah Sultana said Ms Mirza was “utterly unsuited” to the role and her involvement “shows how little the Government cares about tackling systemic racism”.

Home Secretary Priti Patel said Ms Mirza was the victim of an “orchestrated pile-on” after a series of Twitter users condemned her involvement in the commission’s establishment.

“Munira Mirza is one of the most talented people working in government,” Ms Patel said.

“She has dedicated years of her life to public service.

“A self-made woman who knows her own mind.

“This orchestrated pile-on is deeply unpleasant.”

Former chancellor Sajid Javid said Ms Mirza was “smart, compassionate and deeply committed to social justice”.

“One of the sharpest minds inside No 10,” he said.

“No wonder the Left don’t like her.”

The Prime Minister’s official spokesman said the commission will be chaired by an “independent figure” who will be announced “in due course”.

“Munira is the Prime Minister’s head of policy, so you would expect her to be involved in setting this up,” the spokesman said.

Ms Mirza, who served as one of Mr Johnson’s deputy mayors while he ran London, used an article on the Spiked website to criticise the Lammy review in September 2017.

She said Mr Lammy implied that BAME people did not trust the justice system because of “institutional bias and discrimination”.

Ms Mirza wrote: “Certainly there is a historic legacy here from previous decades, but it is equally possible that the current accusations of institutional racism by lobbyists and activists – a perception more than a reality – is behind the further corrosion of public trust.”

In a Sun article that month, she said: “By appeasing the anti-racism lobby and affirming its culture of grievance, public institutions and business leaders are not making Britain a fairer place but harming the very people they aspire to help.”

Mr Johnson defended his commission on Monday, following criticism that action rather than another review is needed.

The Prime Minister, who also faced a backlash for saying he wanted to stop the “sense of” victimisation and discrimination, later acknowledged that racism “unquestionably” existed in the UK.

He told reporters in Downing Street: “The whole point of having a review is to look at the areas where people feel there’s more that needs to be done.

“I think what we want to do is learn now very fast what fresh changes we need to make.”

Downing Street said the review would also examine poor educational outcomes for white working-class boys.

The new commission will report directly to Mr Johnson and also be overseen by equalities minister Kemi Badenoch.