LONDON, SEPT. 6 -- Britain's Parliament, meeting in emergency session for the first time since the Falklands War eight years ago, voiced overwhelming support today for the Western military deployment in the Persian Gulf, but there were also strong warnings that a shooting war could break the consensus here and abroad.

Prime Minister Margaret Thatcher announced that Britain is considering sending additional forces to the gulf, and there were published reports tonight that these might include 2,000 ground troops to supplement the three British aircraft squadrons and half-dozen warships already there or en route. Thatcher also announced allocation of $3.8 million in additional relief funds for refugees in countries bordering Iraq, bringing to $10.3 million Britain's total commitment of humanitarian aid.

Thatcher and Labor Party leader Neil Kinnock appeared in total agreement on the steps taken under U.N. Security Council endorsement to isolate Iraq and force it to retreat from its month-long occupation of Kuwait. But Thatcher insisted that the United States and Britain could justifiably launch a military strike against Iraq without needing to return to the Security Council for approval.

In contrast, Kinnock warned that such an action, while perhaps defensible legally, would destroy the international solidarity that has been a prime achievement during the crisis. Kinnock told a packed House of Commons that a joint Anglo-American attack on Iraq could lead to "further turmoil, terrorism, an increase in nationalism and fundamentalism and the destabilization of strategic allies" in the Middle East.

"These are the reasons," Kinnock said, "why it is important strategically . . . that everything possible is done to ensure that if further military action is necessary, it should be taken under the full authority of the United Nations."

Wary of what is known here as the "Falklands effect" -- the big boost in popular support for Thatcher after the South Atlantic conflict that carried her to a second electoral victory -- Kinnock has enthusiastically backed the government in its deployment of armed forces and its support for President Bush. Polls so far have suggested that while most people support the government's actions, the crisis has had little impact on the way they would vote in the next election.

Analysts said Kinnock put just enough daylight between Labor's position and that of the ruling Conservatives today to allow him to distance Labor later if the military operation ends in disaster or prolonged and costly stalemate.

While he expressed his differences with Thatcher in muted and conciliatory tones, others were more blunt. Tony Benn, a member of Labor's left wing who frequently opposes Kinnock, warned of "the real anxiety that people think America may go to war and Britain, which is quite a minor part of the operation, would be dragged into it."

Benn said that the United States -- after invading Grenada and Panama and supporting Iraq following its 1980 invasion of Iran -- had no moral authority to lead a crusade against Iraqi leader Saddam Hussein. Its real motive, he declared, was low oil prices: "They're hooked on this cheap fluid. . . . These things had better be said, because no one else will say them."

Thatcher won general expressions of praise and support from both major parties, but there was strong emphasis on the need to work through the United Nations and an undercurrent of anxiety that surfaced repeatedly during the session, which concludes Friday with what is expected to be an overwhelming vote of support.

A handful of moderate lawmakers expressed reservations, including former prime minister Edward Heath, Thatcher's predecessor as Conservative Party leader, and Paddy Ashdown, leader of the minority Liberal Democrats.

"We do accept that the use of force may have to be the ultimate {answer}, but it has to be that -- the last option," said Ashdown, a former Royal Marines officer. "I have learned from bitter personal experience that when the armchair theorists start talking of surgical war, it is time to run for cover. . . . If there is a war, I believe that it will have unimaginable and incalculable consequences.

"Measured force of last resort supported by moderate Arab nations, by the European Community and by the Soviet Union is one thing," he added. "But a rash Anglo-American military adventure undertaken unilaterally would be another."