Trying to figure out whether or not the future Queen of England is pregnant is a national parlour game as old as Divine Right, as Kate Middleton is no doubt well aware by now.

Prince William, fresh back from the Falklands, has whisked his wife off for a few days skiing in Verbier, Switzerland. The UK gossip magazine Now is confidently predicting that the couple are to use the vacation to ‘start trying for a baby’, but the smart money says there may already be a bun in the oven.

Weary as Kate may be of the unrelenting focus on her womb, the fuss is entirely predictable in a hereditary monarchy. And now, there has been a renewed bout of speculation on the possibility that she may be pregnant after a flurry of unusual betting activity with two of the UK’s biggest bookmakers prompted them to cut their odds by around 15% in recent days.

So-called ‘novelty bets’ on celebrities lives, political announcements and other national events are a long-established feature on the UK gambling scene, where you can bet on anything from what an expectant Prime Minister will call their child to whether or not it will snow on Christmas Day in London (here’s a tip: it won’t).

Although novelty bets account for less than 1% of the big bookmakers overall business, unusual betting patterns and dramatic shifts in odds around these novelty bets can provide surprisingly accurate forecasts of events, as the propositions are completely vulnerable to insider knowledge in a way that the normal fare of bookmakers - horse races and sports games - are not. For example, in recent years, bookmakers have suspended betting on a range of novelty bets involving weighty issues such as who will become the next coach of the England football squad to the equivalent of who killed JR in a UK soap opera after a flood of money for one choice indicated someone may have got hold of the equivalent of the post-dated sports almanac in the movie Back To The Future.

Whilst one might not be surprised to hear that impecunious soap opera scriptwriters and football administrators have occasionally cashed in on their privileged knowledge, those connected to the Royals have shown they are not above suspicion either. Last year before the royal wedding, the bookies simply closed the book on what colour hat the Queen would be wearing for William and Kate’s big day, and refused to take any more money. There was so much cash for yellow, in preference to any other colour, that it was clear that people with privileged information about the Queen’s outfit were seeking to cash in.

Is the same thing happening here? Not yet. The bookies say that the money for Kate being pregnant (officially, the bet is that her first child will be born in 2012, but by this stage in the year the two are interchangeable) is not at the stage where they are refusing to take any more bets, but they are tightening up the profit margin on the bet and continuing to monitor their daily field books closely.

Both Ladbrokes and Paddy Power have cut the odds on Kate giving birth in the current year. Both bookmakers previously offered the bet at odds of approximately ‘6-4’ (meaning if you wagered $1 you’d get $1.50 back, plus your stake money gets returned) but the price has now come in to ‘8-11’ (translation for non-gamblers: risk $11 to win $8, but again, remember that if you win, you get your stake back as well as your winnings).

Ken Robertson, of Paddy Power, said, “We saw a great deal of money two weeks ago when the price was 7/4. Usually you’d just get a few ten or twenty quid bets on something like this, so when you see people coming in and having a hundred quid – and there were plenty of hundreds and lots of fifties in a tight timeframe – then you sit up and take notice. But since we came into 8/11 it has been quieter.’

Alex Donohue, of Ladbrokes, said, “In short, the odds have changed by about 15%. It’s not a fortune being staked, but the amounts are enough to raise eyebrows in a market like this.”

Does he think Kate is pregnant? ‘I wouldn’t have an idea, but the money isn’t usually far wrong.’

It was widely believed that Kate was pregnant last year, and the rumours were fuelled when Kate declined to sample peanut paste during a trip to UNICEF’s global supply centre in Copenhagen, and then refused champagne for water when hosting a charity dinner on behalf of Prince Charles.

Also adding to the intrigue late last year was a very sudden change in the rules of succession. The new rules mean that if Kate and William’s first born child is a daughter, the girl will accede to the throne not a younger brother. The way the announcement was rushed out by the government suggested to some suspicious minds that Kate was pregnant.

But the rumours came to nothing, and whether or not Kate had a miscarriage, as the Globe recently reported, or she was never pregnant in the first place, remains unknown. There is also a question mark over Kate's weight.

Kate and William have both spoken publicly about their desire to start a family, and while Kate may be a decade older than Diana, who conceived within months of her marriage, she is only 30. Even if the latest round of rumours prove unfounded and nothing were to happen baby-wise for a couple of years, Kate and William still have plenty of time.

Kate has proved herself to be a patient woman. It’s just a pity the same cannot be said of the British public.