The first prime minister's questions of 2012, and the main topic was Scottish independence. We will hear of little else for the next few years. Already the debate has achieved a mad, surreal air. For example, someone in No 10 must have thought to themselves: "What the Scots really hate are posh, arrogant, public school-educated Englishmen who know what's best for everyone else. So let's put George Osborne in charge of the campaign to keep Scotland in the UK!"

Perhaps it's a double bluff. As the SNP MP Angus Robertson pointed out on Tuesday: "The Conservative party has fewer MPs in Scotland than there are giant pandas in Edinburgh Zoo." If Scotland does break away, it could guarantee Tory governments at Westminster for the foreseeable future.

So perhaps David Cameron is secretly in favour of breaking up the UK, and knows that the more he (and George Osborne) bang on about the need to keep the nation together, the more likely Scots will vote for separation. He stresses how much we all have in common, including "shared economic interests". I wonder if that includes the £65bn shovelled across as a bailout for the great Scottish banks, RBS and HBOS, more than £3,500 per English household?

(Jock McBraveheart, Scottish political commentator: "That is a disgracefully misleading statistic. Scottish taxpayers had to find just as much money, not to mention the jobs lost north of the border." Me: "You think that's disgracefully misleading? Wait till you see some of the rubbish that'll be churned out over the next two years.")

Meanwhile, the SNP position is even more confusing. As elucidated by Mr Robertson yesterday, the party won a large majority in the last Scottish election with a promise to hold a referendum. But because they have such a big majority, they have the right to hold the referendum whenever they please, ie when they think they are most likely to win it. The SNP's rousing battle-cry is: "Scotland demands the right to choose freedom! But not quite yet."

David Cameron and Ed Miliband appeared to be entirely in agreement on the topic of Scottish independence, with Mr Miliband perhaps slightly more earnest, given that at Westminster elections the Scots still tend to vote Labour. He made his main assault on the topic of rising rail fares, which he blamed on the government. Mr Cameron blamed them on the last Labour government. No doubt both are right. Or possibly both wrong. But the rises are happening under the Tories, so we may assume that passengers will blame them anyway.

The prime minister was slightly rattled. For example, towards the end of the session he was asked by Tony Lloyd about the fact that the chief executive of a Footsie-100 company can earn 35 times as much as a hospital consultant, who saves people's lives.

Mr Cameron – like any good PR man he has spotted an issue that affects the public, and belatedly supports it – said that he was all for success being rewarded, "but we should not have rewards for failure". He went on: "Frankly, the last government had 13 years to deal with this, and did sweet nothing."

"Sweet nothing"? The phrase is "sweet fuck all", sometimes euphemised to "sweet FA" or "sweet Fanny Adams". "Sweet nothing", being both vulgar and twee at the same time, has no meaning, other perhaps than a curt reply to the waiter's question: "Can I tempt you with the dessert trolley?"

When the newly endamed Joan Ruddock, formerly of CND, asked a question about a constituent likely to be thrown out of her home because of cuts in housing benefit, the prime minister ignored the question and launched into a mock-gallant tribute to her honour coupled with an assault on her wish to "disarm Britain one-sidedly".

For once, the combined and noisy fury of the Labour sisterhood – Harriet Harman and various Eagles – alarmed him enough to force him to give her a proper response. Possibly a first. Ed Balls could never have managed it.