The chaos over this terror legislation reflects the lack of trust in Tony Blair

The Home Secretary, Charles Clarke, concedes more ground. A judge will decide whether suspects should be placed under house arrest. The Government's original proposals are no longer under consideration. Parliament and most of the media rage about the dangers of a supposedly mighty executive, yet it is MPs and the Lords, cheered on by the media, who have tamed the supposedly arrogant ministers.

The Home Secretary, Charles Clarke, concedes more ground. A judge will decide whether suspects should be placed under house arrest. The Government's original proposals are no longer under consideration. Parliament and most of the media rage about the dangers of a supposedly mighty executive, yet it is MPs and the Lords, cheered on by the media, who have tamed the supposedly arrogant ministers.

At Prime Minister's Questions yesterday, Mr Blair adopted his "I have no reverse gear" tone over the anti-terrorist legislation, but he had already applied his much-used lever by granting a more extensive role to judges. As Mr Clarke stated in the debate yesterday afternoon, in extreme cases he would have preferred the elected politicians to take the immediate decision. He is not alone. As far as I can tell, judges are not seeking the powers that Parliament seems determined to impose on them. Most of the judges interviewed in recent days express concern about being placed in a pivotal role. In effect, they will be making decisions about the nature of the threat to national security and the most appropriate way of dealing with it.

As I argued last week, there is a strong case for ministers, not judges, to exercise emergency powers in extreme situations. Ministers are responsible for national security and accountable for their actions. We have seen over the last fortnight how accountable they are. Even with a landslide majority, Mr Blair and Mr Clarke have struggled to get their way. It has been suggested in some quarters that the Commons was craven and the Lords more assertive. This is not the case. The first concessions were announced to restive MPs last week. Even after the concessions were made, the Government's majority was reduced to 14 and would have been wiped out completely had some Liberal Democrats bothered to vote. Most of the time it is a myth that British governments - and Prime Ministers in particular - can do more or less what they like. Quite often they feel overwhelmingly constrained, even this administration with its massive landslide. Especially this administration with its fears of alienating parts of the media and so-called middle-England voters.

Yesterday's debate in the Commons also revealed again that, for all the huffing and puffing, most MPs recognise that house arrests might be necessary. The problem for Mr Blair is partly a matter of trust and credibility after the war against Iraq, an episode in which he did assert excessive Prime Ministerial powers and, I suspect to his surprise, he did so with a majority of public and media opinion against him.

There is a revealing contrast between the current row and a similar situation during Labour's first term. After the IRA attack in Omagh in the summer of 1999, Mr Blair rushed through draconian anti-terrorist legislation, not quite as sweeping as the current proposals, but wide-ranging and unprecedented in scope. Some political lawyers were alarmed, as they are now, but on the whole the mood was supportive. Mr Blair was still enjoying a honeymoon with the voters and the media. He was trusted.

The intelligence relating to suspects in Britain is more forensic than material relating to Iraq. When Mr Blair and Mr Clarke assert that the intelligence points to real dangers, I believe them. Other ministers not known for getting over-excited tell me that - to quote one of them - "some of this stuff is really frightening". Mistakenly, Mr Blair placed equal weight on the tendentious intelligence relating to Iraq. He cannot escape the origins of the war, as the related row over the unpublished legal advice from the Attorney General also illustrates.

Trust is a nebulous issue. In the 1970s, when inflation soared, few worried about trust in public life. Similarly in the 1980s, as unemployment rose, there was no fevered analysis of the trustworthiness of elected politicians. It is a theme that has surfaced now partly because the economy is performing so well. In the absence of more pressing themes, the subject whirls around British politics.

I keep on bumping into people who insist that Mr Blair lied in the build-up to the war. When I ask at what point he lied, they say vaguely, "He lied over the weapons." This implies that in advance of the war, Mr Blair made a calculation along these lines: "I've got it. Let's pretend Saddam has got weapons of mass destruction. When the war is over and they discover he did not have any, we will ... well, what the hell will we do then?"

A closer examination of what happened suggests that Mr Blair got himself in a disastrously contorted position in his frenzied attempts to build up support for the war. He became too dependent on unreliable intelligence, but there is no evidence to suggest that he knew there were no weapons. Like his decision to make a premature commitment to support President Bush, a matter of judgement has metamorphosed into one of trust.

This has wider implications beyond the current political row. Securing the trust of the electorate was the essence of the early New Labour project. Every sentence uttered and every policy formed by Mr Blair and Gordon Brown was aimed at winning the trust of the voters and the media after 18 years of opposition. Their ruthless focus culminated in a cautiously incremental manifesto at the 1997 election and the granting of independence to the bank of England in the immediate aftermath. The independence of the Bank of England was driven more by political motives than economic policy: We are not trusted, so we will give power away over the control of interest rates. At some point a future Prime Minister will need to make a similarly big gesture to restore trust in the political process.

Meanwhile, the battle over Mr Clarke's proposals is taking up so much parliamentary time that next week's pivotal pre-election Budget is starting to seem like a piece of light entertainment, a brief respite for an afternoon. One senior government insider compared the bizarre pre-election dominance of this issue to the sudden eruption of foot and mouth before the last election in 2001. Ministers had not planned or anticipated the legislative chaos, a sign that their antennae are no longer sharp as they used to be.

The electoral implications, though, are far from clear. The Conservative leadership risks accusations of opportunism over national security, not a comfortable political position. Some Conservative MPs are uneasy. While the Government has changed its approach with an awkward clumsiness, the Conservatives have leapt from one stance to another. In the space of a few days they have moved from firm opposition to conditional support and back to opposition again.

Both Mr Blair and Mr Howard are keeping their eyes on public opinion, not healthy for either of them. With the Lords ready to resume the battle today, that is the clearest point of all. A pre-election period is not a time for sensible and candid debate on any issue, let alone for one as sensitive and complex as this.

s.richards@independent.co.uk