On the surface at least, 1986 looks to be a good year year for Western European economies, marked by continuing, although slower, increases in growth and declines in inflation and interest rates.

But, as London-based Phillips and Drew investment counselors caution, "complacency regarding such developments could be dangerous." In a metaphoric assessment that reflects hedged bets across a wide spectrum of analysts, they note that "February 9 marks the beginning of the Year of the Tiger. According to Chinese belief . . . an explosive year."

The explosions could come in the forms of: Europe's predicted failure to make a significant dent in persistently high unemployment rates; and ongoing volatility in the international oil market -- where a modest price decrease of about 10 percent is an asset, but anything more is seen as causing problems not only for Europe, but for most of the developed world.

"Growth in the community will probably continue in the medium term, without, however, exceeding 2.5 percent a year," said the European Commission in its annual economic report. "This could bring about only a modest improvement in the employment situation."

Others are more pessimistic. Noting that Europe already has the highest rate of joblessness in 50 years, the Paris-based Organization for Economic Cooperation and Development forecasts that it is likely to remain at about 11 percent, or just over 19 million people. At the same time, the labor market is likely to become increasingly polarized, with those longest out of work becoming more unlikely to find it.

In most European countries, the effect of unemployment has been assuaged to some extent by moderation in wage increases. This has not been the case, however, in Britain. Despite having the highest unemployment rate in Europe, about 13.5 percent, Britain also has recorded pay rises averaging around 7 percent or 8 percent -- "well above the level which the economy can support through productivity growth," according to one analyst.

The Bank of England notes that declining export competitiveness of British goods -- a factor of high production costs and the strengthening pound -- and high unemployment and wages combine to create "acute dilemmas" for policy makers.

Lower interest rates or a weaker pound, said a recent bank report, would provide only temporary and inflationary relief from competitive pressures.

At the same time, the benefits of North Sea oil production create special dangers for Britain. Overall, as production nears its peak, according to analysts at London's Capel-Cure Myers, "it is likely to exercise a negative influence on GDP growth by 1987."

Most analyses are calculated on the basis of oil prices stabilizing at about $24 a barrel, a figure that many acknowledge may prove to be wishful thinking.

The government of Prime Minister Margaret Thatcher has pledged tax cuts this year, a crucial vote-getter as the country moves toward general elections by 1988. Yet, the government loses more than $200 million for each one percent drop in sterling oil-prices, and recent price reductions already have cost the treasury nearly $1.5 billion.

Economic analysts Simon and Coates predict that oil revenue may drop to about $10 billion in 1986-87, compared with $16 billion this year -- again assuming the price stabilizes at $23 to $24. Thus, although revenue will continue to be bolstered by the sale of state-owned industries, the scope for tax cuts now is viewed as only one-half as large as the government originally had hoped.

Politics also has played a large part in recent economic developments in France, where the economy last year began responding to austerity measures adopted by the socialist government in 1982 and 1983. Inflation is down, the rise in unemployment appears to have been checked, and the once-chronic balance-of-payments deficit is disappearing.

As it moves toward important legislative elections in March, the government has seized upon the improvement in the basic economic indices as evidence that a left-wing government can manage the economy as effectively as the right.

In its annual report, however, the OECD painted a more cautious picture. Noting that the cut in the French inflation rate to under 5 percent was about average for European Community countries, it added that France was vulnerable to competition from its main trading partner, West Germany, where inflation is only half as much.

Other French economists again pointed to continuing high unemployment as a danger signal -- with more than 2.5 million French citizens out of work as a direct result of the government's austerity plan to reduce demand.

Among the major European economies, best prospects are seen for West Germany. In addition to low inflation and relatively low unemployment, production is up to an estimated 85 percent of industrial capacity, and the deficit has been slashed to $9.4 billion, only about one percent of GNP. Growth is expected to be slightly higher than the 2.5 percent predicted for Western Europe as a whole.

The biggest problem the Germans will face this year is continued pressure from the United States to stimulate their economy, a policy with which they have fundamental disagreements.

While the government of Chancellor Helmut Kohl has pledged tax cuts by 1987, it believes that any further stimulus is likely to produce more inflation that it does jobs.