LONDON (AP) – Prime Minister Tony Blair lost a crucial parliamentary vote Wednesday on sweeping new legislation allowing police to detain terrorism suspects for 90 days without charge _ the first major defeat of his premiership and a serious blow to his authority.

Instead, lawmakers, including some from Blair’s own Labour Party, voted for a maximum detention period of 28 days without charge.

Lawmakers blocked Blair’s original proposal by a 322-291 vote, and then approved the modified plan by an almost identical 323-290 vote.

“We were trying to do the right thing for the country,” Blair told the British Broadcasting Corp. after the vote. “We know there’s terrorist threats there.”

He also said he could not understand why lawmakers were putting “the civil liberties of a small number of terrorist suspects” before the public’s “fundamental civil liberty” to be protected from terrorists.

Defense Secretary John Reid described the result as a “big loss for the country, a loss for the fight against terrorism, a loss for the police, and a loss for the government.”

The outcome prompted the leader of Britain’s main opposition party to say Blair should reconsider his position as prime minister.

Blair had refused to compromise over his plan. Knowing the vote could the tightest of his eight years in office, Blair recalled two Cabinet ministers from overseas trips to shore up support.

Blair appeared tense and shook his head as the first result was read out.

The Terrorism Bill was drafted in the wake of the July attacks on London’s transit system. The proposal, intended to curb Muslim extremism, would outlaw training in terrorist camps, encouraging acts of violence and glorifying terrorism.

It must be approved by Parliament’s upper chamber, the House of Lords, before becoming law.

Wednesday’s result is humiliating for Blair, who took a major political gamble in refusing to back down on the plan. He called back Treasury chief Gordon Brown from an official visit to Israel that was only two hours old, and he also ordered Foreign Secretary Jack Straw to cut short an official European Union visit to Russia.

Labour Party chairman Ian McCartney, who is recuperating from heart surgery, volunteered to return to work for the vote.

The current maximum detention period for terror suspects without charge is 14 days, and critics argued that extending it to 90 days would erode civil rights.

The result raises serious question about Blair’s grip on power. His popularity slumped due to the unpopular war in Iraq, and some Labour lawmakers now regard Blair as an electoral liability.

Opposition Conservative Party leader Michael Howard said Blair’s authority was “diminished almost to vanishing point.”

“This vote shows he is no longer able to carry his own party with him. He must now consider his position,” he said.

Blair’s official spokesman disagreed, saying the vote was a “one-off.”

“We did not see this as a matter of confidence in the prime minister as this was a proposal put forward by the police,” the spokesman said on condition of anonymity, according to policy.

Blair has said he will not seek a fourth term in office, and although he could serve as prime minister until 2010, there is pressure for him to quit sooner.

Left-wingers in the party have long been unhappy with his plans for greater private sector involvement in state-run hospitals and schools. Many want Blair to step aside in favor of Brown, a powerful and popular figure in the party.