British political realignments flow from nation's shifting social structure

Deep changes in Britain's social structure underlie the current shifts and jockeying for position on the surface of British political life. At the same time, national debate has intensified about the method by which the British cast their votes. Although no quick changes are likely, support for a change to proportional representation has been growing since the alliance of the Social Democrats and the Liberals pulled in one-quarter of the popular vote, but gained a mere 23 seats - or 3.5 percent - in the House of Commons.

Among the social changes, say analysts of the election results such as Prof. Ivor Crewe of Essex University:

* Blue-collar workers are shifting away from radical socialism and toward more centrist views.

Their views appear rooted in rising home ownership and, apart from the unemployed, a slowly improving standard of living. Latest figures show rises in consumer spending and in the percentages of households owning cars, telephones, central heating, refrigerators, freezers, and washing machines.

* The opposition Labour Party still relies on working-class votes - but trade unionists and even the young unemployed switched in large numbers to the Tories as well as to the alliance on June 9.

Almost as many trade unionists voted Tory as voted Labour. Among the young unemployed (18-22 years old), half did not vote at all, and less than one-fifth went Labour.

All the parties are studying changes like these, and arguing about how to translate them into concrete political terms.

To the prime minister, the results are a resounding vote of confidence - although Professor Crewe and others see it as more of a rebuff to Labour and a flirtation with the alliance.

Mrs. Thatcher's immediate post-election task was to ensure that her basic monetarist policies would be carried out by people close to her and her views. She has made about 60 changes in a list of about 100 senior, middle, and junior ministerial positions at the top of government.

By no means has she purged the ''wet'' (liberal Tory) wing of the party. One of the most prominent, Francis Pym, was summarily sacked as foreign secretary, but others, including Peter Walker (moved from agriculture to energy) and James Prior (at the Northern Ireland office) remain.

Her basic aim, aides say, has been to promote younger men and give wider experience to others already in government. She promoted eight backbenchers, gave 11 ministers more senior posts, and dismissed or accepted resignations from 14. It is also true she wanted to reward those closest to her, and those who helped secure her large reelection margin.

These facts explain Sir Geoffrey Howe moving from chancellor of the Exchequer (treasurer) to the job he wanted as foreign secretary; Nigel Lawson rising from energy to treasury secretary; Leon Brittan from treasury to home secretary; Cecil Parkinson from Tory Party chairman to the secretary of a combined Ministry of Trade and Industry, and Ian Gow, her former private secretary, to minister for housing and construction.

Meanwhile, a series of realignments are taking place among the ranks of the opposition.

On the one hand, with Labour leader Michael Foot's resignation prematurely announced by a union leader, a struggle has started among the center, moderate left, and radical far-left for control of the party in the next few years.

As Professor Crewe's research shows, the social underpinning of the Labour Party changed on June 9. The party lost 9.3 percent of its overall vote, as the electorate turned away from Mr. Foot's radical policies of giving up nuclear weapons, leaving the European Community, and borrowing money to create jobs.

Leading the race to succeed him at this point is Neil Kinnock, a relatively young Welshman and close friend of Mr. Foot, who also supports unilateral disarmament and who wants Britain to pull out of the EC.

Already, left-wing unions are lining up behind him, including the Transport and General Workers' Union and the Communication Workers. This alarms more moderate unions, who see a Kinnock victory as continuing the leftist, unilateralist image that lost Labour so many votes on June 9.

On the sidelines are finance spokesman Peter Shore, in the moderate left, and Roy Hattersley, to the right.

The struggle will continue until October, when the Labour Party holds its annual conference in Brighton. Trade unions hold 40 percent of votes to be cast for the leadership. The other 60 percent are split between Labour MPs - who now contain more left-wingers than at any time in recent years - and grassroots constituency parties (CPs). One reading here is that the far left can put together enough votes from trade unions, MPs, and CPs to elect Mr. Kinnock.

Meanwhile, the Social Democrats and the Liberal Party are holding strategy sessions of their own.

Roy Jenkins, the originator of the idea of the SDP in 1981, stepped down from leadership to allow Dr. David Owen, a much younger man and effective on television, to lead the party. Dr. Owen is more to the left than Liberal leader David Steel, and wants to keep the SDP's separate identity as a left-center alternative to the Labour Party.

Mr. Steel favors close links between Liberals and the SDP, and is maneuvering to silence vocal Liberal critics who see the SDP, with only six seats in the new Parliament, as very much junior to the Liberals, who have 17.

On changing the method of voting, the 99-year-old Electoral Reform Society favors the Irish system. Voters would number candidates in order of preference. When a candidate reaches a quota high enough to be elected, his preference votes would be assigned to others, until all seats are filled.

Elected November 1980 July 1982 party February 1975 Announced July 1976 Announced Leader resignation resignation June 12 July13 Representation 397 seats 209 seats 17 seats 6 seats in 650-seat (144 seat Majority) Alliance = 23 seats Percent 2.6% 0.9% seats in 61% 32% Alliance = 3.5% Parliment Percent 13% 11.6% popular vote 42.4% 27.6% Alliance = 24.6% in June 9 election