The Home Office has turned out to be a graveyard for new Labour politicians. David Blunkett and Charles Clarke were forced out after they failed to get to grips with a dysfunctional department. Although John Reid jumped before he was pushed, he too struggled to cope with rising prison numbers and a series of crises involving escaped prisoners. His solution was to split the department in two just before announcing his resignation. Only Jack Straw, the great survivor, left with his reputation intact.

Jacqui Smith, whose appointment by Gordon Brown took everyone by surprise, has no illusions about her chances of longevity. The gallery of portraits of her predecessors outside her office has already given her pause for thought. "I have taken the trek along the corridor and looked at the whole row of home secretaries. I think it's in order to inspire you, but also to demonstrate that you are moving through," she says.

It is not Straw or Clarke that she chooses as her role model, but Blunkett, with whom she worked at the Department for Education for two years. "My first ever boss as minister was David Blunkett, and David has always brought something very special to ministerial life," she says. "I think in terms of his ability to communicate the challenges we face in government and [I] never forget that success as government is the impact we have on communities and those that serve us." She also pays tribute to Roy Jenkins, Labour home secretary during the 1960s, as a reformer. But she baulks when we ask if she would like to be seen as a "liberal" in the Jenkins tradition. "No," she says without a moment's hesitation. "I'd like to be seen as a home secretary that made a difference to people feeling secure and enabling them to get on with what they want to do in their lives."

Her politics were forged by experience in her constituency, Redditch, a Worcestershire marginal that has stayed in Labour hands through three elections thanks largely to the local MP's appeal to the values of Middle England. She has long argued that Labour must hold to the centre ground if it is to win the trust of voters in seats like her own. "I come at this very much from the point of view of someone with a marginal constituency," she says. "I have to build the broadest possible coalition within my constituency, which seems to be a microcosm of what we've managed to do as a government and will carry on doing."

This does not mean being illiberal, she says, "but being pretty tough about representing the concerns of those who elected us and making sure we deliver on them". In practical terms, this involves giving extra powers to local communities to hold local police to account. That is why she has ordered the monthly publication of local reports on how crime and antisocial behaviour are being tackled.

"You cannot continue to make the progress we've seen in reducing crime if you don't engage with people at a local level in determining what the issues are they want to see addressed and being part of the solution as well. If people feel more engaged at a local level you have a result on everything from terrorism to antisocial behaviour. People also feel more confident about the society they live in." She remains unconvinced, however, of the need for locally elected police chiefs. "Having an elected police chief is shorthand for 'we want more accountability'. Of itself, I don't think it would deliver that."

It may be tempting to see Smith as gentler than her predecessors, partly because she is a woman and partly because of the calm way she approached the failed terrorist attacks in Glasgow and London on her first weekend in the new job. But, on all the most pressing issues, she is a hardliner in the tradition of Blunkett and Reid rather than an instinctive liberal like Clarke. On extension of the 28-day period of detention without charge, on identity cards, on penal policy and on immigration, she is, if anything, more convinced about the authoritarian approach than the tough guys who came before.

Dark omens

The 28-day issue has become the first battleground for civil liberties under the Brown government. The omens are not promising. Smith says although she cannot cite an example of an existing case that would have benefited from an extension, she is certain it will be needed in the future. She believes it is responsible to have the argument now about the balance between protecting human rights and catching terrorists, rather than wait for an emergency. "I don't see it as talismanic," she says. "Am I looking for a fight on the 28 days? No. But am I looking to make sure that I can be confident that the police and those who need to investigate terrorist plots have got . . . everything they need in order to be able to do that? Yes." We ask her to clarify: is the status quo among the various options being discussed? She admits it is not. "I have been persuaded that at some time in the future . . . we will need to be in a position where, in very rare situations, we may need to go beyond 28 days."

On ID cards, she is even more dogmatic. Although the Brown government has initiated reviews of policy on casinos, cannabis and 24-hour drinking, there is no turning back on this. Some had wondered - it now turns out to be wishful thinking - if Brown, during his hesitant first Prime Minister's Questions, had been bounced into restating the government's commitment to ID cards. The hope was that he didn't mean it, that ministers might eventually shelve the scheme in the face of protests or rising costs.

Not a bit of it, says Smith. "You do need a system which has at its heart the ability, at a national level, to tie people's identity to a record of who they are." It has been suggested that it would be possible to have an identity database, but no physical card. On this point, Smith, again, is crystal clear. "There will be an ID card," she says. "From 2009 we will be introducing ID cards for UK citizens. From 2008 we will introduce what will effectively be an ID card for those who have been in the UK for more than six months."

Nor will liberals find comfort in Smith's approach to criminal justice policy. Despite record prison numbers and increasing disquiet over indeterminate sentences, "Putting more people in prison is not an end in itself, but it might be part of the solution to reducing overall levels of crime." We put to her Clarke's concerns about prison numbers. "He was right to be bothered, because the number of people you put in prison is a representation of the amount of crime you've got . . . but you can be bothered without then arguing that you should fundamentally change the nature of your sentencing, or that you should reject as wrong a decision you took previously on indeterminate sentencing."

Much has been made of Smith's calm approach to the failed terrorist attacks at Glasgow Airport and outside a London nightclub. We wonder whether she had deliberately avoided the emotive language of the "war on terror", concentrating on the criminal nature of terrorism. "It is a conscious approach," she says, "and it's a conscious approach that stems from the need to enlist the broadest possible coalition in order to tackle terrorism . . . So, yes, it's tone, but the tone is fundamentally linked to the approach you need to take to counter terror."

Asked what she thinks of the specific phrase "war on terror", she is again frank: "It is not one that I used. It seems to me that what we should be doing is emphasising the values that we share which are under attack from terrorism, rather than trying to create a battle or war between those who oppose the terror and those who want to carry it out."

Smith is a fierce advocate of Brown's "hearts and minds" approach to tackling the radicalisation of young Muslims. She also believes that Muslim communities have not been best served by their leaders. She backs moves, put in place by Ruth Kelly when she was communities secretary, to broaden the kinds of groups with which the government engages and cut out, for example, the Muslim Council of Britain. "We've got to make serious attempts to go beyond those who have previously been seen as leaders of the community. She was absolutely right to do that. We have seen, in the immediate aftermath of the Glasgow and London bombings, that the response from leaders of the community was better because of the action previously taken."

Jacqui Smith: the CV

l3 November 1962 Born in Malvern, Worcestershire, daughter of two teachers

1979 Joins Labour after local Tory MP, Sir Michael Spicer, speaks at her school

1981-84 Studies PPE at Hertford College, Oxford. Runs unsuccessfully for president of student union before being elected chair of National Association of Labour Students

1986 Starts career as an economics teacher

1997 Elected Labour MP for Redditch as "Blair babe"

2003 After stint as one of youngest ministers in DoH, is appointed deputy minister for women and equality, driving civil partnerships legislation

2005 As minister of state for schools, funds Lesbian and Gay History Month

May 2006 Joins cabinet as chief whip in Blair's fraught last reshuffle

January 2007 Brands Celebrity Big Brother producers "shameful" in racism row

28 June 2007 Selected by Gordon Brown as first female home secretary and second youngest since Winston Churchill

29 June 2007 Survives baptism of fire with failed car bombings in London and Glasgow

July 2007 Dubbed "Jacqui Spliff" after admitting to experimenting with cannabis at university

Research by Matthew Holehouse