Margaret Thatcher, treading a delicate path between Poland's Communist leaders and restive opposition, was applauded warmly by a crowd of Poles Thursday as she began a program of sightseeing and official talks.

The first British prime minister to visit this Soviet bloc country, Thatcher was greeted with spontaneous applause by several hundred Poles after she laid a wreath at the Tomb of the Unknown Soldier in Victory Square.She was heading for her official car, but turned and went back to the crowd to shake a few hands before heading on to meet government officials.

Thatcher was to have her first talks with Polish leader Gen. Wojciech Jaruzelski later in the day.

On Wednesday, the communist party chief issued a veiled warning to his British guest not to interfere in Poland's tense politics.

In the Baltic port of Gdansk, where Thatcher planned to travel Friday for a meeting with Solidarity leader Lech Walesa, nearly the entire 10,000-member work force of the Lenin shipyard rallied on Wednesday.

The workers vowed to fight the government's decision, announced Monday, to close the yard where Solidarity was born during a 1980 strike wave. Walesa even said his banned free trade union movement would work for the first time with its government-backed rival.

Thatcher will be the first Western leader to make the symbolic trip to meet Walesa at his headquarters in Gdansk.

The government said Monday it planned to close the Lenin shipyard on Dec. 1 for economic reasons, though Walesa called the move an attempt to weaken Solidarity. The yard would be the first large enterprise shut down in a new goverment attempt to revive a limping economy.