He has become the outspoken voice of the Liberal Democrat left – yesterday calling for the party's MPs to be given the power of veto over contentious Coalition policy proposals.
Last weekend, Simon Hughes, the deputy leader of the Liberal Democrats, firmly rejected suggestions that Tory and Lib Dem candidates should step aside in each other's safest seats at the election. He has also made clear his disquiet over moves to raise VAT and encourage the opening of "free schools".
But far from being a thorn in the side of the Liberal Democrat high command, senior colleagues said yesterday they were not dismayed by his candid style, or by his enthusiasm for appearing in front of television cameras.
In fact, the left-winger is deliberately acting as a useful lightning conductor for discomfort among members about the difficult decisions the Coalition is taking – and may not be as far away from the leadership as some suggest.
His presence helps to remind the public, and reassure activists, that the Liberal Democrats – the Coalition's junior partners – are maintaining their separate identity in office. That is a crucial task for the party in the face of plunging opinion poll ratings.
"His job is to give us a distinctive voice and he is doing that very successfully," a senior Liberal Democrat figure said. "We would be concerned if he was harming the Government, but that isn't happening."
Mr Hughes's pronouncements also help Mr Clegg remind Mr Cameron that there is a limit to how far the Liberal Democrats can be pushed. However, Mr Clegg's allies dismiss "conspiracy theories" that his deputy's interventions are planned in advance and sanctioned to demonstrate the distance between the two governing parties. They argue that Mr Hughes is such an "unspun" character that schemes of that kind would be impossible to achieve.
There is little doubt, though, that he is a convenient figure to have articulating the party's voice outside Government. Where his predecessor, Vince Cable, helped to give the Liberal Democrats gravitas and intellectual clout, Mr Hughes is a reassuring presence for left-leaning voters. They now know that there is no prospect of an electoral pact with the Tories at the next general election, that the alliance with David Cameron is business rather than pleasure and that the old, left-of-centre dream of an anti-Tory pact has not been written off for all time – just for the next five years.
Mr Hughes is now heading off for a bird-watching holiday on the Black Sea. When he returns, he faces the challenge of rallying the Liberal Democrat troops at their conference without undermining Mr Clegg's leadership.
He and his government colleagues will face an even more onerous task shortly afterwards when they begin work on the policy platform that will eventually be presented to the voters in 2015.
Mr Hughes will be among the loudest voices arguing they must present a distinctive, radical programme to the electorate – and that they will be punished by the voters if they fail to answer the question: "What are the Liberal Democrats for?"