Brize Norton AFB, England — Prime Minister Margaret Thatcher has urged the Soviet Union to take the next step in arms control with the United States by agreeing to reduce drastically the numbers of strategic (long-range) nuclear warheads. Meeting with Soviet leader Mikhail Gorbachev for two hours yesterday, Mrs. Thatcher welcomed with enthusiasm the treaty to eliminate shorter- and intermediate-range missiles which is to be signed in Washington today. She expressed hope for an early agreemnent to reduce by 50 percent strategic nuclear weapons on both sides.
``What so far has been achieved promises more to come,'' the British prime minister said.
Only a few hours before Mr. Gorbachev was to be in Washington, Thatcher urged him to demonstrate good faith in his desire to improve relations with the West. This should include progress on human rights as well as the withdrawal of Soviet troops from Afghanistan in 1988, she said. She also pressed her case for extending the Antiballistic Missile Treaty which she said would increase confidence between Washington and Moscow.
The British prime minister reiterated a proposal for a joint timetable between the two superpowers for research on their strategic defense programs. Thatcher included this proposal in a letter sent to President Reagan last week as a means of getting around the impasse posed by Washington's Strategic Defense Initiative (SDI or ``star wars'') in the past.
Since Mr. Gorbachev admitted last week that the Soviets have been pursuing their own star wars program, the prospects for some agreement on this issue appear more likely, Thatcher said.
In a brief statement on his first visit to Britain since 1984, Gorbachev commented that the road to agreement on eliminating intermediate-range nuclear missiles was ``not an easy one.'' He also referred to hopes for a ``non-nuclear world.''
``We expect our visit to Washington...will help us move forward on the road to restructuring international relations, to a better and deeper cooperation and mutual understanding,'' he said before boarding the plane for his first visit to the US.
After the Soviet party took off from this air-force base in the English countryside, Thatcher warmed to the role of world statesman in a meeting with the press. She described herself as ``not a go-between'' but ``a staunch and loyal ally of the US'' who had important interests at stake in the agreements reached between Washington and Moscow. She strongly defended Britain's own nuclear deterrent of four Polaris nuclear submarines and warned against premature visions of a non-nuclear world.
``I see no scope for further reductions in nuclear weopons in Europe until conventional weapons are brought into balance and chemical and biological weapons are eliminated,'' she said. She reported that Gorbachev was sympathetic to the view that an agreement is needed on reducing these weapons. Thatcher said she was not expecting any suprises at this week's summit and hoped that any new ideas which might come from it would be carefully considered before commitments were made.
Thatcher showed admiration for Gorbachev, describing him as a ``determined and courageous leader'' who deserves the encouragement of the West for his efforts in reforming the Soviet system.
``What was outstanding was his intention to drive on with perestoika and glasnost and to apply the same intention to drive on with arms reduction,'' she said of her two-hour discussions.
``We talked in animated debate as always,'' she said referring to her previous meeting with Gorbachev when she visited Moscow in March. She added, ``The atmosphere was very, very good indeed'' and that relations between the Soviet Union and Britain were ``better than ever before.''