I followed the local elections in London and in Somerset. If one had to choose a mayor of London from the characters in Shakespeare's plays, there is no doubt one would have to choose Falstaff. He combines a big personality, a shrewd intelligence, a certain reputation where women are concerned, an eye for the main chance and an enduring warmth. So far, London voters have consistently voted for the candidate who most resembled Falstaff in character; Boris Johnson is now closer than Ken Livingstone, who has never been sure whether he was playing Falstaff or Jack Cade.

The most successful mayors of New York, such as the great wartime mayor, Fiorello LaGuardia, have come out of the same mould. They have given personality to a great city. I doubt if Boris will ever be called “the little flower”, but he will personify London. He will also add to the innocent amusement of the nation.

I expect him to be a good mayor; he is highly intelligent, basically good-natured and a surprisingly skilful politician. David Cameron will find him a nuisance from time to time, but he will be amply rewarded in additional votes. Boris Johnson may make it fashionable to vote for the Conservatives; he makes Toryism fun.

I'm certain he will not change. He was a contemporary of members of my family when he was at Oxford; I have heard him being discussed for the past 20 years. In that time he has not changed, and I cannot see why he would change now. One can safely disregard the stark warnings of those who have never liked him. He poses no threat except to political rivals and to attractive young women of nubile age.

Boris Johnson has done something very important. He has won London for the Conservatives against the most skilful London politician since Herbert Morrison, who led Labour in London to the great 1945 victory. London is the leading city of the nation and by far the wealthiest. It is always a strong influence on British politics. London usually leans to the left, as most big cities do.

Only an exceptional Conservative politician can take the lead in London and deliver the big city for his party. Boris's London victory makes an overall Conservative victory at the next election far more likely. I do not expect the Conservatives to throw that away.

Before 1997, Tony Blair, who is an extremely astute politician, foresaw the possibility of a great reversal for Labour. He never thought that it would be quite as bad as the 2008 local elections, with the loss of London. Mr Blair saw that it was easier to win elections when Labour and the Liberal Democrats were working together, formally or informally. In 1997 and 2001, Labour gained greatly from tactical voting. Mr Blair tempted Paddy Ashdown with a coalition and Roy Jenkins with electoral reform. If he had needed to do so, Mr Blair might have delivered, but he won large victories which blocked these ideas of a grand coalition of the Left. Perhaps that was a missed opportunity.

However, the 2008 results may well tempt some politicians to revive the idea of a Lib-Lab pact. After all, the Conservatives won 44 per cent of the national vote; the Lib Dems won 25 per cent and Labour 24 per cent. One does not need to be a senior wrangler to calculate that 25 + 24 = 49 and that 49 is a larger sum than 44.

Some readers may have noted the paragraph yesterday in Atticus, the Sunday Times column. Atticus reported that, on election night, “Charles Kennedy urged BBC viewers to keep an eye on the Somerset result. That would, he said, be particularly significant.” “Yet,” Atticus commented, “Somerset did not go to the polls last week.”

It was, in fact, Atticus and not Charles Kennedy that was mistaken. There was a Somerset county council by-election in Mendip North East and the Lib Dems did expect to win it - not without reason.

The Mendip seat had been held by the Conservatives in 2005, on 44.8 per cent of the vote, with 39.3 per cent Lib Dem and 16.3 Labour. In last Thursday's by-election, Labour did not contest the seat. The Lib Dems hoped to pick up most of the Labour vote.

Two Lib Dem MPs were seen early last Thursday morning waking up the voters of Coleford. This seemed to be the opportunity for the Lib Dems to show that they could take a Somerset seat off the Conservatives. At the previous election, the combined Lib Dem and Labour vote had been more than 55 per cent, 11 per cent more than the Conservatives. It seemed an open goal.

The Conservatives had a young local candidate, Matthew Ellis, who, last year, had won a seat on the district council. The Lib Dems pulled out all the stops; so did the Conservatives. I know about this because our youngest daughter, Annunziata, is the Conservative parliamentary candidate. The result was that Matthew Ellis won with 51 per cent of the vote, a majority of 71.

The absence of a Labour candidate did not therefore result in the election of a Lib Dem. Charles Kennedy was right to tell BBC viewers that the Somerset seat was significant. With a combined Lib-Lab vote of more than 55 per cent, it ought to have been a Lib Dem gain. But voters cannot be relied on to do what the parties want.

In test-bed conditions, the Mendip voters were not interested in a Lib- Lab tactical vote. No doubt a Lib- Lab pact will remain a temptation, but I do not think it is possible to negotiate and I do not think it would be won. So long as the Conservatives can get 51 per cent of the vote, they do not need to fear a pact of the Left. Last Thursday's results show that the Cameron strategy of aiming for the centre ground has been a considerable success.

Times Recommends

• Tear down this wall! And save the planet
• Double click if you want the bin emptied
• Have you got permission to read this?