Former Ugandan president Ysusfu Lule flew to London today after having been detained in Tanzania for two weeks following his ouster by Uganda's new revolutionary parliament.

Lule, 69, who became president after Tanzanian forces and Uganda rebels toppled dictator Idi Amin in April was accompanied to the airport by Tanzanian President Julius Nyerere.

Lule's top aides and members of his family in London have insisted that he was being held against his will under armed guard here. They said he was asked daily to sign a pledge of support for his successor, Godfrey Binaisa, who was named by the Ugandan parliament with the apparent backing of Tanzania.

Tanzanian officials had denied the charges until today, when authorities acknowledged that Lule had been an unwilling guest in the Tanzania state house. The officials said Nyerere frequently conferred with Lule in an effort to persuade him to renounce his claim to Ugandan presidency.

The Ugandan Consultative Council ousted Lule June 20, accusing him of ignoring democratic procedures after two controversial Cabinet reshuffls in the space of a week. His removal and replacement by Binaisa led to several days of rioting in the Ugandan capital Kampala. The disorders eventually subsided.

Both Lule and Nyerere declined to answer reporters' questions at the airport. After arriving in Nyerere's presidential limousine, the two men -- former classmates at Scotland's Edinburgh University -- walked in silence to the waiting British Airways plane.

A British doctor and relatives said Lule was in ill health and needed medical attention in Londn.

Upon arrival in London, Lule was taken straight by ambulance to Hamersmith Hospital.

"I think he is very, very ill," said Lule's son, Waswa. "He has a blood disorder. I have not been told exactly what is the matter with him."

[Lule's son said his father, who walked to the ambulance aided by a walking stick, was going to Hammersmith Hospital for a checkup. Before leaving the airport, Lule stood for a few moments and waved to about 30 Ugandan supporters who came to the airport to greet him. He smiled broadly as they called friendly greetings to him.]

Meanwhile, Tanzania has begun withdrawing its estimated 40,000 troops from Uganda, officals here said Nyerere has said some Tanzanian forces would remain behind to maintain security and help train a new Ugandan army. CAPTION: Picture, YUSUFU LULE . . .held in Tanzania against his will