The last Prime Minister's Questions of the year had an inevitable Christmas theme. And I don't mean silly hats, crackers, family rows and rubbish presents.

It was David Cameron who kicked it off when he started cracking jokes about the large, noisy beast flapping around in front of him which he would dearly love to see stuffed for Christmas.

Having read a tabloid story that Ed Miliband might be ready to sack his shadow chancellor (really? I mean, really?) he declared: "You don't need it to be Christmas to know you are sitting next to a turkey."

That woke up deputy prime minister Nick Clegg until he realised Cameron was talking about Miliband and Balls.

Non-denial of the week

London mayor Boris Johnson provided the Christmas entertainment for political journalists in Westminster with a classic turn that mixed pointed political jibes with the usual befuddled jokes.

Clegg took the brunt of it when Johnson was asked for his thoughts on the performance of the deputy prime minister.

"He is a radio disc jockey now, isn't he," he said in reference to the deputy PM's weekly radio phone-in programme.

"He is a lapdog of David Cameron who has been converted by taxidermy into a kind of protective shield. Like the Emperor Valerian (now you knew there would be a classical reference didn't you?) who was skinned and hung on the wall, that's what he reminds me of.

"He is a very, very decorative part of the constitution. So far as he fulfils any function at all it is to stop sensible policies being promulgated by this government.

"The sooner we are shot of the great yellow albatross of the Liberal Democrats, the better," he said.

Funny, Clegg speaks very highly of Johnson (cough) and I'm sure, given the opportunity during his next radio show, he will make his support for the would-be Tory leader very well known.

Can't wait.

Ambitious denial

Johnson was also ready for the inevitable question about his future ambitions and, in unusually frank style, gave what appeared to be a straight answer to the question of whether he fancied being Tory leader.

"I cannot imagine I will be called upon to serve in that office," he declared with absolute candour.

Well, he might not be able to imagine it but there are plenty of people on the Tory benches who can.

Quote of the week (it was a bad week)

As Johnson told the assembled hacks how wonderful it was to be back in the palace of Westminster (hint, hint) amongst all the Victorian architecture and ancient gargoyles there was a very brief hesitation as we all waited for someone to fill in the joke.

Step forward Tory whip Claire Perry who offered: "Labour MPs", luckily too quietly for most to hear it.

Builder's estimate

The palace of Westminster is falling apart. That much is known. Even the super rats who are regular spotted around the place have been seen packing their bags in preparation for moving out sooner rather than later.

And yours truly found a large chunk of the ceiling in his office next to Big Ben had detached itself and landed on a colleague's work station.

"That's the leaky roof that's caused that," suggested a helpful repairman. Yes, we knew. This must be one of the few offices in London where you need an umbrella indoors.

Anyway, to the point.

The House of Commons Commission has finally set about employing someone to carry out a detailed study of what needs doing and how soon. My advice would be soon!

The contract has gone to Deloitte Real Estate and will get under way early next year with a decision of how to proceed being taken in the next parliament.

The betting is that MPs will have to agree to move out of the palace, possibly for years, while the "very significant renovation" of "a great iconic building" is undertaken.

Oh, and the cost of the investigation? A very reasonable maximum of just £2,019,295 with a fixed price "which may be lower but not higher agreed two months into the contract once the consultants have become familiar with the extensive survey work already done on the palace."

Cue sharp intakes of breath and sucking of teeth.

Somebody in the building trade is in for a very nice little earner.