Secretary of State James Baker arrived late Saturday in Britain, the second stop on his 14-nation, six-day tour of European NATO capitals to explain the Bush administration's foreign policy.

Baker, who will meet Prime Minister Margaret Thatcher and Foreign Minister Geoffrey Howe on Sunday, flew to London from Iceland, where he met his counterpart and discussed issues involving the U.S. military presence in Iceland.NATO will be at the heart of the new administration's foreign policy, Baker told reporters on his flight to Iceland from Ottawa, where he accompanied President Bush on a visit Friday with Prime Minister Brian Mulroney.

"The NATO alliance will play a central role, not only as a military alliance but as a community of common values and interests," Baker said.

He listed four other basic starting points for the new administration's foreign policy:

-The United States is committed to maintaining its military strength while also continuing a "dialogue with the East," primarily the Soviet Union.

-The administration is determined to play a constructive role in promoting a settlement of regional conflicts around the world.

-The United States recognizes the importance of collective international action in dealing with such things as the environment, drugs and terrorism, but the administration also reserves its right to act alone if necessary.

-The Bush administration is committed to open international trade.

Baker said he is making the whirlwind trip to European capitals to explain these policies to his NATO counterparts as well as to listen to their views.

During the rest of Baker's week, he will travel to Germany, Denmark, Norway, Turkey, Greece, Italy, Spain, Portugal, Belgium, Luxembourg and France, as well as a refueling stop in Ireland.

"We want them to be in on the takeoff so they will be with us on the landing," Baker said of the allies.

While the State Department is reassessing policies through 28 separate reviews, the new administration wants to build on progress made by the Reagan administration in such areas as arms control.

Baker said he will have his first encounter with Eduard Shevardnadze in Vienna on March 6 at the opening of the conventional arms reduction talks.

The visit to Iceland was a short one, with time only for a two-hour meeting with Icelandic Foreign Minister Jon Baldvin Hannibalsson at the airport at Keflavik, about 45 minutes outside the capital of Reykjavik and adjacent to a large U.S. military base, before leaving for London.

The whirlwind tour will give Baker an opportunity to establish personal relationships with his European counterparts, a process he has found valuable in the past, he said.