One should not over-elaborate the analysis of elections. The central question is always the same. Who won? This is certainly true of the Norwich North by-election, where Chloe Smith turned Dr Ian Gibson's Labour majority of 5,459 in 2005's General Election into a Conservative majority of 7,348.
Allowing for all the special circumstances, that is probably a good enough result to produce a Conservative victory next year, both nationally and in Norwich North. That is what matters; it is natural for the Conservatives to be delighted with last Thursday's result as well as relieved. Miss Smith is more than entitled to enjoy her triumph.
There are, however, some interesting undercurrents revealed in the Norwich North results. First, there is one piece of excellent news, which I had not totally expected. After its relatively successful result in the European Elections, the British National Party (BNP) thought it a good idea to put up a candidate in Norwich North. It was mistaken. The BNP was beaten into seventh place with just 941 votes.
That does not mean the BNP may not become a future threat, but it does show it has limited appeal outside a few deprived areas. Seventh place in a by-election is a joke position for a group claiming to be a national party.
The result put the Conservatives in first place, Labour second, the Liberal Democrats third, the United Kingdom Independence Party (UKIP) fourth and the Greens fifth.
The result is disastrously bad for Labour. Undoubtedly, Labour voters resented the brutal dismissal of Dr Gibson, a popular and independent-minded local MP. The Labour vote fell by 70 per cent from 21,097 in 2005 to 6,243 in 2009. The opinion polls have been reporting that Labour support in the country has fallen from 36 per cent at the last General Election to a figure in the mid-20s now. Norwich has confirmed the opinion polls reflect reality.
The Conservatives won the seat largely because Labour has become so unpopular. In 2005, the Tories came second in the Norwich seat with 15,638 votes; in last week's by-election they came comfortably first with 13,591. The Tories would have been able to win the seat simply by retaining the support of their past voters, though they did well to increase their share of the votes.
The Lib Dems also had a lower vote in 2009 than they had had in 2005. At the by-election they came third, but they had only 4,803 votes to the 7,616 they had won in 2005. Although Labour did by far the worst, all three traditional parties won fewer votes than they had won at the last General Election.
The three leading parties, taken together, saw their vote fall from 44,300 in 2005 to 26,700 in 2009. Resentment over parliamentary expenses may have partly caused the decline, but an analysis of the vote for the new parties suggests there is more to it than that.
Two of the new parties came just below the three traditional parties in the ranking order. Both had performed reasonably well in the European Elections. UKIP increased its 2005 vote from 1,122 to 4,068 at the by-election. That put it in fourth place. Indeed, UKIP was fewer than 1,000 votes behind the Lib Dems. The Greens increased their General Election vote of 1,252 to 3,350.
Both parties are perceived by the public as single-issue parties. Nevertheless, both were able to increase their votes at a by-election in which the three major parties were unable to do so. Labour's vote was catastrophically lower. Obviously, the European and Green issues are important to voters.
Last week, Labour lost some 15,000 votes, votes that Dr Gibson had won in 2005. No doubt many of these voters simply abstained, but the two new parties gained 5,000 voters.
If Britain had adopted electoral reform, which is the long-standing policy of the Lib Dems, these new parties, including the BNP, would have an opportunity to grow to the point at which they would become natural coalition partners. The parties that are the biggest threat to the established parties would also make the most attractive coalition parties.
The Lib Dems would be attractive coalition partners for Labour, as they have been in Scotland; UKIP might be a potential coalition partner for the Tories, though that would be resisted. The Greens are a threat to the Lib Dems, but could also be their partners. As we do not have proportional representation, this change-your-partners dance will not take place - yet.
Nevertheless, British politics will increasingly be influenced by the single-issue parties. It is no longer reasonable to think UKIP or the Greens are merely crankish parties, bound to fade away. The opinion polls suggest both are in the interesting situation of being single-issue parties whose issues have strong public appeal. Most voters are certainly more conscious of Green issues than they used to be a generation ago; most voters have also become increasingly critical of the European Union and the Lisbon Treaty.
The Lib Dems in the House of Lords voted with the Government against the Lisbon referendum, which the country had been promised. Obviously, Eurosceptics will hesitate before they vote Lib Dem. Support for Green issues crosses the boundaries of other parties - the Tories can claim to have been a Green party for a long time in that they were always the countryside party.
I would not particularly welcome coalitions of conflicting ideas - which electoral reform has created in Scotland - into Westminster. But I do welcome the mixture of ideas which is fermenting in our politics. The Norwich North result supports the forecast that Labour is on the way out and the Tories are on the way in.
Yet it also supports the view that the politics of ideas, which we knew in the Forties, may be coming back. It was the ideas-based parties, UKIP and the Greens, which were the only ones to increase their votes in the Norwich North by-election.