IT was, perhaps, the longest, most vigorous handshake in Whitehall history.

Outside the Scotland Office, a beaming Alistair Carmichael was excitedly yanking the arm of his leader Nick Clegg following his elevation to the post of Secretary of State for Scotland (a post he wanted to abolish in opposition). There were no reports, however, on whether the Deputy Prime Minister found the Carmichael treatment a bruising experience.

The change of guard at Dover House was certainly a bruising experience for Michael Moore, whom colleagues insisted had done a fabulous job as Scottish Secretary. Yet they were more reticent, defensive even, on just why Mr Clegg had decided to change the Borders man for the northern Viking.

The only reason the DPM gave was that he wanted to draw on a "different experience" while, when asked what qualities, different to Mr Moore, he would bring to the role, Mr Carmichael made clear he was not going to attack his predecessor.

Yet there were rumblings a year or so ago that consideration was being given to replacing Mr Moore with his "old pal" from Orkney. Question marks were gently raised as to whether the genial giant was, ahem, just too nice a chap and that what was needed was "a bit of stick"; as Francis Urquhart might have said.

The rumblings subsided as the ­technical process for the referendum got under way and the delicate negotiations with Deputy First Minister Nicola Sturgeon moved forward. It was here that the benefits of Mr Moore's diplomatic skills were much appreciated by his superiors.

Yet, once the Edinburgh Agreement was signed, the rumblings began to re-emerge; was the Scottish Secretary being assertive enough, people asked.

As the party conference season got under way in Glasgow with the gathering of the LibDem clans, an undercurrent of reshuffle talk got going. The focus was on the Tories and Labour, not the yellow peril; it was also on the middle ranks, not the Cabinet.

When the axe fell it must have been particularly painful for Mr Moore, whose office in Dover House is just feet away from Mr Clegg's; the two LibDem guardians would have chatted to each other pretty much every single day.

Mr Carmichael has spent much of the week pleading how he is not just the one-dimensional pugilist many have made him out to be and that there is "light and shade" to his character.

Having declared he is "fired up", the new Scottish Secretary has insisted he wants to de-personalise the referendum campaign and focus on the issues. One can only say good luck; those lovely cybernats have already dubbed him Bagpuss in deference to his non-bruising qualities.

Of course, it could just be that in his reshuffle Mr Clegg was looking beyond the horizon; that having got through the bruising experience of the independence campaign, there was then the bruising experience of the General Election campaign to get through just six months later.

But one comes before the other and Mr Carmichael will be hoping that next September he will again be vigorously shaking Mr Clegg's hand and not waving goodbye.