The Sketch: Euan watches as Daddy gets caught by a low blow from Duncan Smith

The Christmas spirits were disappearing fast from the Commons gift shop yesterday lunchtime as MPs, including the Defra Minister, Margaret Beckett, tripped over Commons staff to beat their way to the special "Members-only" queue.

They emerged laden down with boxes of Commons mints or booze. Mr Speaker's 10-year-old single malt was the popular choice for constituents requiring more than just the official Commons Christmas card. In recent years, two new lines, "Commons Fudge" and Commons Humbugs have also proved popular.

There was also plenty of the latter during the exchanges between David Davis and John Prescott that provided the warm-up act for Prime Minister's questions. Mr Davis – it was reported yesterday – leads, with Eric Forth, the "Doc Martens tendency" within the Shadow Cabinet. It believes in robust, strident, forceful opposition but is rivalled by the touchy-feely modernising tendency known as the "Russell & Bromley group" led by Theresa May, the party chairman, and named after her famous "shoe speech" at the autumn party conference. But the exchanges between Mr Davis and the Deputy Prime Minister were bogged down in the mire of local planning decisions and the Green Belt. This muddy subject required stout footwear and the slugging between these two got nowhere. They would be better off in the Wellington boot group.

Mrs May, however, lived up to her new reputation with a dazzling and astonishing display of footwear. She had on a pair of black ankle boots embroidered in a psychedelic multi-coloured floral pattern. This brightened up Tory spirits that were decidedly low at the start of the session. The recent polls had put them in the doldrums and they looked sad, chastened and thoroughly dejected. For Mr Duncan Smith, facing them later in the day at a meeting of the 1922 Committee, this question time was merely a practise run. It started badly but he had only used two bullets out of his ration of six. They were about Iraq – and misfired. But, just as we were about to write him off, his capacity for surprise – by which he won the leadership against the odds last year – gave him the best one-liner of his career. "Isn't it the case that when the Prime Minister makes promises on schools, transport, pensions, or for that matter on crime, asylum, drugs or health, he's not juggling balls – he's talking them?" It was a Christmas cracker of a question – even though Michael Heseltine, Mr Duncan Smith's bête noire, inspired it. Lord Heseltine had used a similar line, years ago, against Gordon Brown and his adviser Ed Balls. But IDS surprised everyone: Tory MPs, Labour MPs, the Prime Minister and even himself at his success. It was cheap, it was below the belt, it verged on the unparliamentary (had he cleared it with the Speaker, I wondered, as he nodded to Michael Martin afterwards) but it was a winner.

Mr Blair looked taken aback. This was a day he had to score, not least because his eldest son, Euan – he of the Bristol flat – was home from university and watching in the gallery, no doubt expecting Daddy to trash IDS. Unfortunately, Daddy got punched in full view of Euan. How embarrassing. And how satisfying for IDS as he marched off to quell, albeit temporarily, any trouble in the 1922 Committee.