Nick Clegg has fired the Scottish secretary in a bid to install a more aggressive figure to take on Alex Salmond.
With just a year to go until the referendum, Michael Moore was sacked to make way for Alistair Carmichael, who impressed observers recently with his conference speech.
The new man in the job said he was up "up for it" as he arrived outside No 10 this morning.
"I believe we now need to draw on different experience in the final year running up to the referendum itself," Clegg wrote to Moore.
Moore replied that he was "very disappointed" to lose his job and said he had done it "pretty effectively".
Moore did not commit any significant gaffs during his three years in the post but his moderate, even-handed style clearly fell out of favour with Clegg, who has opted instead for a more direct and aggressive figure.
Some analysts have questioned the wisdom of that judgement. Many thought that Moore's reasonableness – for instance by never questioning that Scotland could survive as an independent nation – robbed Salmond of his ability to wrap himself in patriotic rhetoric.
The change is expected to be the only Cabinet-level alteration in this week's reshuffle.
Long time Lib Dem MP Don Foster was installed as the new chief whip.
He was replaced at the Department for Communities and Local Government by Stephen Williams, who sits on Politics.co.uk's editorial board.
Meanwhile, Jeremy Browne was dropped from the Home Office, to be replaced with Norman Baker.
That move was particularly interesting given Baker believes the Home Office was complicit in the death of weapons inspector David Kelly.
He will be replaced at the Department for Transport by Susan Kramer.
"It is always very difficult to move colleagues out of government but as you know, I have always been keen that we provide the opportunity for as many in our ranks as possible to contribute their skills to ministerial office during this parliament so that, just as the government has benefited from your contribution over the past three years, it can also gain from those of other colleagues ," Clegg wrote to Browne.
It's thought that Browne's sacking is a result of him not being on top of the 'racist vans' programme before the pilot scheme.
But the Baker promotion could cause Clegg some new headaches, as passages from his book are promoted online showing his views on the death of Kelly and even Robin Cook.