Elections: Voters show unprecedented degree of dissatisfaction: Ivor Crewe, Professor of Government at the University of Essex, examines the way electors chose to cast their votes on Thursday

This week's extraordinary results in Newbury and the shire counties displayed two significant features. The first was the sheer scale of voters' disaffection with the Government. The second was the unprecedented efficiency with which voters chose an opposition party as the vehicle for that disaffection. The consequence was the Conservative Party's most humiliating by-election defeat since the Second World War and its worst local election result this century.

Even by the hyper-standard of by- election defeats, Newbury was spectacular. The 29 percentage-point slump in the Tory vote was the largest in any comparable post-war by-election, exceeded only at Sutton in December 1972, and goes beyond anything incurred in the Thatcher years.

The 28.4 per cent swing from Conservative to Liberal Democrat puts Orpington (26.8 per cent), Crosby (25.5 per cent), Ribble Valley (24.8 per cent) and other celebrated Liberal trophies in the shade. It has been exceeded only once - again, at Sutton - but there the Liberals started from a much lower base.

Newbury counts as the more significant achievement because the Liberal Democrats added such a large vote to what was already a high starting point. In the past, Liberal advances have bumped up against a 45 to 50 per cent ceiling in Tory rural and suburban strongholds. In the 1984 by-election in Surrey South West, for example, a socially similar constituency also voting one year into a parliament, the Liberals could only add 11 points to their high base. This time they broke through the ceiling.

The Conservative debacle cannot be blamed on stay-at-home supporters - as perhaps the county election defeats can - because at 71.3 per cent the turnout was high for a by-election.

Nor is tactical voting by Labour supporters the explanation: the Labour vote had already been reduced to 8 per cent in 1987 and 6 per cent in 1992. The additional squeeze to a mere 2 per cent - the smallest share of the vote Labour has ever received in a parliamentary constituency - shows that even Labour loyalists will vote tactically. But it cannot account for a 28.4 per cent swing. The only possible explanation is that huge numbers of dissatisfied Conservatives voted Liberal Democrat in protest.

The county elections reflected a similar degree of anti-Government animus. Whether measured in terms of council control, seats or votes, the results were disastrous for the Tories. Councils they have run for more than 100 years, such as Norfolk and Surrey, were lost. Labour is now the largest party on - of all places - Suffolk County Council. Liberal Democrats control more county councils than the Tories. The number of Conservative councillors is the smallest in the existing system of local government.

Only the raw voting figures offer a crumb of comfort to the Conservatives. The estimated national equivalent of the shire county vote was Conservative 31 per cent, Labour 41 per cent, Liberal Democrat 24 per cent, others 4 per cent. The Conservative share is exactly in line with recent national polls. It is fractionally lower than at any previous post-war local election, but close to 1985, when it dipped to 32 per cent.

Yet the Tories managed to win handsomely at the general election two years later. Labour's 41 per cent, however, is six to seven points below its apparent support in the polls, which suggests that some of its support is not easily converted into real votes. The Liberal Democrats' 24 per cent is an exceptionally large local bonus to its national support of 17 to 18 per cent, but still below the 27 per cent that the old Liberal-SDP alliance reached in the mid-1980s.

Even so, the Liberal Democrats and Labour won a record number of seats because their vote was more efficiently distributed than ever before. Rarely if ever before has the centre won seats in proportion to its vote as it did on Thursday. It did so because voters treated the election as a choice between not three parties, but two: the Conservatives and the Strongest Not-Conservative Party. Two different two-party systems operated in parallel: the traditional Conservative-Labour contest in the big towns; the new Conservative-Liberal contest in the suburbs, small towns and country.

What were voters protesting about? Not 'Europe', as the paltry vote for the anti-Maastricht Conservative candidates in Newbury shows; but the recession, or more particularly the Government's handling of it, and the lack of conviction or inspiration from Downing Street. Thursday's results showed a deeper disillusion than at previous mid-term nadirs.

Compare the most recent Gallup poll, for example, with the one conducted exactly 12 years ago when the equivalent county elections were held in the midst of the equally savage 1980-82 recession. Then as now half the electorate reported a deterioration in their family finances; then as now only one in five were optimistic about the next 12 months; and then as now the Government and Prime Minister were unpopular. But their unpopularity had not plummeted to the same degree. In 1981 only 23 per cent thought the Government was handling the economic situation properly, but now the proportion is down to 15 per cent.

Perhaps the 1980-82 recession was accepted as a necessary purgative for the British economy, or partly blamed on the previous Labour government. Perhaps Mrs Thatcher inspired more confidence than John Major. Perhaps voters in the South are less accustomed to economic downturns than voters in the North. Whatever the explanation, the electorate has been less forgiving and more impatient about this recession than previous ones.