In a House of Lords statement, Foreign Office minister Baroness Symons said the bombing raids had been necessary to disable Saddam Hussein's anti-aircraft defences and to prevent him from attacking his own people.
She said Iraqi defences had increasingly been used to try to shoot down coalition aircraft patrolling the southern no-fly zone across Iraq.
"The threat is real. Saddam Hussein is trying to kill our air crews," Lady Symons told peers.
No apology
Earlier Downing Street had said Britain would not be apologising for Friday's raids, which the Iraqis say killed three people and injured 30.
She said Iraq had launched more attacks on allied aircraft in January than in the whole of last year.
US and British aircraft continue to patrol the no-fly zones which are designed to stop Saddam Hussein's forces attacking political opponents.
"I'm very glad not to be having to stand here today making a statement about our air crew being shot down," said Lady Symons.
"That was the possible alternative if we had done nothing to take out these installations."
Eight British and 16 American aircraft using long-range precision weapons were involved in the strikes on anti-aircraft sites near Baghdad. All returned safely.
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International backing for the raids has been conspicuously absent, with Russia and China among the first to criticise them, followed by others including France and Turkey.
Over the weekend thousands of Iraqis took to the streets of Baghdad in well-orchestrated protests.
He said that history would judge the air strikes in two ways.
"Will they turn out in the wider context to have served peace or the increase in tension?
"And what will they have done for the ordinary people of Iraq?" he said.
Conservative peer Lord Renton asked whether the timing of the raids was connected to the new Bush administration in Washington.
Lady Symons insisted that there was no connection and said she was confident the Conservatives would have taken the same decision.
Weapons inspectors
Labour's Lord Shore of Stepney questioned the relevance of no-fly zones.
"What can we do about getting the UN inspectorate back into the country?" he asked.
Lady Symons replied: "Those sanctions could stop tomorrow if Saddam allowed the inspectorate back into Iraq.
"We have no reason to trust that he is not still pursuing his programme."
They were "premature, totally ineffective, and will only continue to further strengthen Saddam Hussein's hand", he told the BBC.
Shadow defence secretary Iain Duncan Smith said criticism of the raids by countries such as France showed the dangers of setting up a European Rapid Reaction Force.
"The reaction of countries around the EU ranged from absolutely opposed to deeply unenthusiastic.
"The Iraqi operation demonstrates that when the UK and US are together then tough action takes place," he said.
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Although there was broad support for the government in the Lords, the Bishop of Birmingham, the Right Reverend Mark Santer, warned that the raids could increase the suffering of the people of Iraq.
But Scott Ritter, who resigned as head of the UN weapons inspection team in Iraq in 1998, said he had strong doubts about the legality of the air strikes.
Related to this story:
Labour MP attacks bombing raids
(17 Feb 01 | Scotland)
Iraq defiant as allies strike
(17 Feb 01 | Middle East)
Iraqi opposition backs strikes
(16 Feb 01 | UK)
Iraqi press calls for revenge
(17 Feb 01 | Middle East)
Little support for Iraq attack
(17 Feb 01 | Middle East)
Analysis: A tougher line?
(16 Feb 01 | Middle East)
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