Wear your straightest suit and whatever you do, do not dance.

That is the advice one civil liberties lawyer would give to anyone else who, like him, may be called on to attend the odd acid house party or rave as a legal observer.It is vital that all concerned -- organisers, participants, police and lawyers -- are clear about exactly what role the legal adviser is there to play.

'If you want to convince the police you're there as a lawyer, if you're seen dancing, that's not so easy,' he says.John Wadham, director of human rights organisation, Liberty, says civil liberties lawyers -- who may be called on to attend anything from a rave in a ploughed field to a demonstration outside the American embassy -- need to ensure everyone understands their role.

When he has arranged for legal observers to attend events in the past, they have worn tabards to set them apart from the participants.

'When you're a lawyer sitting in your office or attending court, that is a role people understand.

But when you're attending an event as an observer -- a protest or whatever -- that's when the lines become blurred in people's minds,' says Mr Wadham.

The problems may be compounded by the fact that often this kind of work will be done unpaid, which again raises questions about the lawyer's motivation and sympathies.When the lines become blurred, it can occasionally have shattering consequences.

The leading Northern Ireland defence solicitor Patrick Finucane was murdered by loyalist terrorists on the basis that as he acted for alleged republican terrorists, he must have been an IRA sympathiser.However, for most the more real danger is of character assasination, as solicitor Makbool Javaid discovered.

Mr Javaid, head of the discrimination law unit at City firm Dibb Lupton Alsop, was pilloried in the press earlier this year as a supposed 'terror supporter' and, variously described as a 'prominent member', 'leader', 'spokesman' or 'co-founder' of the Muslim group Al Muhajiroun, which had publicly applauded the bombing of US embassies in Kenya and Tanzania.

However, Mr Javaid insists that his involvement with the group was restricted to giving legal advice and acting as observer at a handful of demonstrations.

Until Al Muhajiroun condoned the bombings, Mr Javaid insists he had always understood it to have peaceful aims.

'I knew Al Muhajiroun was an organisation involved in a wide range of educational and social activities consistent with the promotion of Islam,' says Javaid.

He says he was appalled to learn of its support for the atrocity and has now severed all links with the group.The leading civil rights lawyer Benedict Birnberg, who has acted for the Moors murderer Ian Brady and spy George Blake, agrees that it is easy for those representing unpopular causes or individuals to become pariahs.

'It can have devastating consequences -- you can lose all your clients, who think you're bad news,' he says.Mr Javaid's difficulties were compounded, he maintains, by the fact that the group talked up his involvement in order to boost its credibility.

'I have never authorised the use of my name in any Al Muhajiroun document.

It is particularly disturbing to me as a lawyer to find my role misrepresented in this way,' he says.Mr Javaid has impeccable credentials as a civil liberties lawyer -- a masters degree in human rights, articles at Clinton Davis in Hackney, a stint at Bindman & Partners, before joining the Commission for Racial Equality, involvement in several worthy organisations (Justice, Liberty, the Stephen Lawrence campaign, Anti Racist Alliance, Citizens Advice Bureaux, law centres, to name but a few) -- and it has been a bruising experience to discover that none of this saved him from being labelled an apologist for mass slaughter.

It is an experience he is anxious not to repea t.

Mr Javaid says he will be more careful about taking on pro bono clients in the future.

'You've got to cover yourself.

The only thing you can do is have some kind of written agreement with them which says, "these are the boundaries of what I can do for you".' However, he acknowledges he is not aware of a single civil liberties lawyer who currently operates in this way.John Wadham is unconvinced that such a legalistic approach to pro bono clients could ever work in practice.

Almost by definition, many of them will need ad hoc advice, quickly, from a lawyer who is desperately trying to fit in helping them around other fee-paying work.In reality, the only foolproof way for civil liber- ties lawyers to avoid the risk of being compromised could be to avoid potentially compromising situations and clients -- a situation which would leave many unpopular but needy groups and individuals with no way of enforcing their rights.But it is a strategy already being adopted by one civil liberties lawyer who, like Mr Javaid, maintains his reputation was jeopardised when he was misled by a pro bono client.

'I went to the High Court recently to issue proceedings.

When I came out, there were five people sitting on the concrete who'd clearly got copies of the Criminal Justice and Public Order Act.

I guessed they were being evicted.

In the past, I would probably have said to them, "that's interesting.

Do you want any quick advice here?" But I decided not to.

I would have given them advice on the basis of the story they told me.

But who knows who this group were?' Instead, he kept on walking.