The City business partner of Jacob Rees-Mogg has been handed a peerage and job as a senior minister by Liz Truss’s government in a move likely to trigger accusations of cronyism.

Dominic Johnson, a financier who co-founded Somerset Capital Management with Rees-Mogg, was appointed as a minister in the Cabinet Office and the Department for International Trade.

The announcement was slipped out on the government’s website, which said he had been appointed as of Sunday.

“Dominic Johnson CBE was appointed a minister of state jointly in the Department for International Trade and the Cabinet Office on 2 October 2022,” the statement said.

The appointment is likely to be controversial at a time when Truss, her chancellor, Kwasi Kwarteng, and Rees-Mogg face questions about being too close to the City, after the mini-budget handed substantial tax cuts to financiers and the wealthy.

Johnson is a substantial party donor who has given more than £250,000 and was vice-chairman of the Conservative party between 2016 and 2019.

He replaces Gerry Grimstone, the former chairman of Barclays and Standard Life, in his role as trade minister, encouraging inward investment.

The shadow trade secretary, Nick Thomas-Symonds, said it “beggars belief that the Conservatives have appointed an unelected asset-fund manager to the government, who just happens to be a crony party donor”.

Somerset Capital Management is reported to be up for sale, with two of its founding partners now in senior government roles. Johnson recently said he was stepping down as chief executive of Somerset Capital Management.

Rees-Mogg still holds a substantial stake in the investment firm, despite the potential conflict of interest with his role as business secretary.

Oliver Crawley, Partner at Somerset Capital Management LLP, said: “In respect to Dominic Johnson’s new role, we have key person succession plans in all areas of the business, so were well prepared for Robert Diggle to become CEO.

"As two founders are no longer involved in the day-to-day running of Somerset, we are looking at re-organising our capital structure to allow an ownership that is focused on incentivising the next generation of talent in the business.

"Ultimately any steps we take will be driven by what is in the best interests of our clients.”