John Manzoni will remain the director of a brewery, despite starting his new senior role within the civil service. Photo: UPPA/Photoshot

John Manzoni, who starts his new role on Monday, has been given approval by the Cabinet Office to carry on working as a director for SABMiller, a brewing group that opposed the introduction of minimum alcohol pricing. Corporate filings show he takes his salary in company stock and holds shares worth more than £250,000 in the company.

The Guardian has established that Manzoni actually had three private sector jobs at the same time as carrying out his £190,000-a-year senior civil service role as head of the Major Projects Authority since February, which were all approved by the Cabinet Office.

As well as the role for SABMiller, he was chairman of an energy exploration company called Leyshon Energy, which is headquartered in Tortola, in the British Virgin Islands, and paid him £100,000 a year. He was also an adviser to an energy private equity firm, Adamant Ventures, which does not disclose publicly where it invests its funds.

Asked by the Guardian about his extra jobs, the Cabinet Office said Manzoni would step down from the two energy roles when he takes on oversight of the whole civil service on Monday, but he has been allowed to carry on as a non-executive director at SABMiller. He will put his shareholdings in a blind trust, a device that enables someone to hand over the management of certain financial interests to a third party for the duration of a job.

A government spokesman said: “The Cabinet Office is satisfied there is no conflict of interest.

“John Manzoni has declared his interests to the Cabinet Office. Following his appointment as the chief executive of the civil service he is resigning his appointments except for SABMiller, which it has been agreed he can retain, and he is establishing a blind trust.”

However, Manzoni was facing calls to step down from his job with SABMiller. John Mann, a Labour member of the Commons Treasury committee, said Manzoni’s outside work “undermines the fundamental strengths that Britain has given the world as the model of an impartial and independent civil service”.

He said Manzoni should be forced to “declare and resign” from his company directorship to remove any threat of conflict of interest. “Governance and business should be kept separate,” Mann added.

“Successful businesses are hugely important but there should be a clear and visible divide between business and politics.

“We should never have big business people running the civil service. We want them on advising committees and we want their expertise available as much as possible, but not running the civil service – it compromises neutrality.”

Caroline Lucas, the Green MP for Brighton Pavilion, said she felt Manzoni’s extra job was “troubling” and “undermines the responsibilities he’s been charged with as head of the civil service”.

“It is essential he resigns from the role with immediate effect and publicly declares any remaining interests.”

The Cabinet Office did not respond to a question asking whether it would publish a list of Manzoni’s financial interests when he takes on the job.

Manzoni was given the £190,000-a-year position as the government’s first ever chief executive of Whitehall despite criticism of his safety record while an executive at BP following the Texas refinery explosion and his last company, Talisman, being fined over 50 alleged health and safety violations connected with fracking.

He left the world of business to become chief executive of the Major Projects Authority earlier this year, joining Lord Browne, his former boss at BP, in the Cabinet Office.

Browne, who is the government’s lead non-executive director and the chairman of Britain’s leading fracking company, Cuadrilla, was one of six members of the appointment panel who chose Manzoni for the job, though he did not chair it.