A Tory backbencher has hit out at "jobs for the boys" in government after David Cameron drafted Boris Johnson's brother into his Downing Street team.
Adam Afriyie said there were too many ministers, and new posts were being created apparently to "alleviate political pressures".
The Prime Minister appointed Orpington MP Jo Johnson as a Cabinet Office minister last week, giving him a key post overseeing policy. Labour has accused Mr Cameron of trying to buy loyalty in the Conservative ranks by handing out official roles.
In an article for the ConservativeHome.com website, Afriyie - rumoured to be positioning himself as a future party leader - wrote: "In our 2010 manifesto we were committed to reducing the size of government.
"And yet, three years on, it only seems to be growing in size and expanding in reach. To me, this expansion is deeply worrying and rather perplexing."
He complained that there were currently 31 people attending Cabinet on a regular basis, far more than on the boards of even the largest private companies. The overall number of ministers has risen from around 80 in 1950 to around 120.
"Basically, there are just too many government departments, and there are too many people attending Cabinet to make it an effective decision-making body," Afriyie wrote. "This may be uncomfortable for career politicians hoping for a ministerial post or a seat in cabinet, but we must remain true to what we believe."
Earlier this year, the Windsor MP was rumoured to be at the head of a leadership plot against Cameron.
In his article, he questioned why the Department for Energy needed to be separate from the Department for Environment, and suggested International Development could be folded into the Foreign Office.
The Department for Culture, Media and Sport could also be headed by a minister of state rather than a secretary of state, he added.
"It is not that the functions performed need necessarily to be reduced or even given less priority. It just seems to be more practical and business-like to streamline and combine similar functions," Afriyie said.
"In the same way that we have seen job-title inflation in the public sector, we have, sadly, seen our Government follow suit with permanent new jobs and departments.
"I suspect it's more about jobs for the boys and alleviating political pressures. Therefore, I really think we must take a serious look at how our country is governed before there are more MPs on the government payroll than there are holding it to account."
Mr Afriyie suggested introducing "temporary ministers" to act as project managers. "They would focus on specific legislation, major changes, or events such as The Olympics, for example," he wrote. "Once their job was completed they could move on with a sense of satisfaction and achievement - without having been sacked."
He also insisted the government should bring forward less "unnecessary legislation and regulation", and the Commons should sit for fewer days every year.
"If successful we should see a Parliament that sits for fewer days each year, with MPs free to spend more time with the people they serve who live in the real world rather than the rarefied atmosphere of Westminster," he said.
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