Kevin Dunion is standing on a bridge. It's one of those old iron ones bolted together like a giant Meccano set in revamped, yuppified Leith. Between posing for the photographer, he glances nervously at his watch. He's due to attend a bigwig meeting at St Andrews House, and he knows he's going to be late.

The coincidental relevance of the setting strikes me only later for,

of course, 47-year-old Dunion is indeed on a bridge. Behind him lie two decades of campaigning for social and environmental justice as editor of the pro-devolution magazine Radical Scotland, campaigns manager for Oxfam, and, for the past 11 years, director of Friends of the Earth Scotland.

Before him looms the task of supplying teeth to the Freedom of Information (Scotland) Act as the first Scottish information commissioner. His challenge is to convince sceptics that he has taken his placard-waving radicalism with him across that bridge.

We meet at the offices of his PR because as yet the Scottish information commissioner (''no acronyms, please!'') is homeless. No office, no staff, no telephone. Keen to emphasise his independence from the executive, Dunion plans to set up his office in St Andrews, near his home in Anstruther. Interviews for the 12 staff will begin shortly.

He gives a convincing impression of keenness to be up and at it,

following the stramash over his appointment. Unconventionally, and much to Dunion's annoyance, the SNP and Conservative members of the cross-party group of MSPs charged with the selection, revealed that they favoured another candidate: Clive Fairweather, the former chief inspector of prisons and a persistent prickle in the flesh of the executive.

Dunion was once an SNP activist but was one of the group publicly to tear up their membership cards in 1982 following the proscription of the radical '79 Group. Were the Nats bent on revenge against a defector? ''I'm not going to say anything about that,'' says Dunion, smiling broadly.

He deeply resents the accusation that he is a Labour placeman, cosily familiar with McConnell and Co. Dunion happens to be married to Linda Malloch, ex-wife of enterprise minister Iain Gray, but that could just as easily work against him, and he hasn't belonged to any political party for years. He promises he will have no qualms about hammering on the doors of the Scottish Executive if it proves obstructive in providing information to the public.

Dunion has a proven track record of attempting to prise open various locked filing cabinets. At Friends of the Earth Scotland, the only charity to appoint its own freedom of information officer, Dunion extracted a promise in parliament that scientific data on the level of toxic contamination in farmed fish would be made available. ''Nearly two years later, I still haven't received it.''

A survey for FoE Scotland showed nearly 10% of requests for official information went unanswered, and more than 40% of respondents found answers inadequate. So is there a culture of official secrecy in Scotland and are Scots too deferential to officialdom?

''I wouldn't put it like that,'' says Dunion. ''I think there's a culture of 'What's it got to do with you?' around official secrets, commercial confidentiality, and the provision that policy discussions shouldn't be put into the public domain. There's no assumption that information will be available unless there's a good reason why not. Now, if people ask for information and are denied, that isn't the end. They can apply to me. Often in the past I think people were denied information on subjects such as contaminated land for fear of causing alarm.

''In Scotland we have a combination of outspoken grievance but an implicit lack of confidence about the ability to pursue that. People become labelled as troublemakers because they've come to the end of their tether.''

He sees his task as bringing about a culture change. ''We need to make people more confident about their rights to information and public authorities more proactive about making information available.''

It isn't sexy stuff but one of his main tasks is to persuade public organisations vastly to improve the way they manage records. Freedom of information legislation will be a dead letter if the information people want it buried in an official's vast unsorted files of e-mails.

If Dunion is annoyed about the publicity surrounding his appointment, he is incandescent about Fairweather's suggestion that the job could be done on a part-time basis, at a reduced salary, until the act comes into force. The deadline for implementation is December 2005.

At FoE Scotland, one of Dunion's complaints about the legislation was the long run-in to implementation. He is determined to persuade the Scottish Parliament that his operation will be ready to go live long before the end of 2005, possibly the previous January, to coincide with implementation south of the border.

Despite his obvious zeal, it's hard to resist the thought that Dunion is somehow a poacher turned gamekeeper. He winces at an extract from a press interview three years ago, when he said: ''On close inspection, the bill is riddled with flaws that we know will be exploited by government and other bodies to deny information to the public.''

Now he denies there are any loopholes in the legislation and stresses the minor amendments he helped to force through. ''It's difficult for me to criticise legislation I'm there to enforce,'' he says.

I ask what suits him better as a campaigner: banging on the door or sitting round the table inside? ''For years I was better at banging on the door. Now there's much less of an 'inside-outside' culture. I've welcomed access to decision-makers and never felt I had to compromise.''

Aged 10, Dunion was profoundly affected by the Aberfan disaster. At Oxfam he witnessed the devastating impact of the Narmada dam in India on the indigenous population. They honed his convictions about social and environmental justice, catchphrases eagerly embraced by New Labour. It's no secret Jack McConnell has used Dunion as a sounding board on the environment.

So can Dunion remember how to wave a placard? His reply is forceful. ''Remember that drama called The Project? There was one hidebound apparatchik who said, 'I'm not going to be held accountable to the milkman.' Well, it's my job to make officials accountable to milkmen.''

The Act explained

When does the Freedom of Information Act come into force? It is unlikely to come into force before 2005. Meanwhile, anyone denied information by a public authority can appeal to the ombudsman, Professor Alice Brown.

Where is the information commission based? St Andrews, Fife, though most of the commissioner's work is expected to be done via e-mail or phone.

What will the commissioner do? He will decide what information we can access. Anyone denied information from Scotland's public bodies will be able to appeal to him. Public authorities need to respond to inquiries from the public in 20 days. Appeals should be heard within four months.

What won't he do? He won't deal with personal information. This comes under the Data Protection Act, which is handled by the English-based UK Information Commissioner. The same applies to areas of public life not devolved from Westminster. These include military establishments, nuclear power stations in Scotland, and the secret service.