One could never criticise Martyn Day for lacking the willingness to have a go. ‘I’m absolutely determined to find the right case,’ says the senior partner of claimant firm Leigh Day & Co, when asked if he would be prepared to have another crack at suing tobacco companies on behalf of dying smokers.

Day, alongside national firm Irwin Mitchell, took on the almost infinite resources of the tobacco industry in the 1990s on what he once semi-jokingly referred to as a ‘no win, no fee, and possible bankruptcy’ basis. While Day might claim to have been prepared to put his business on the line for the right case and – as he makes clear during the interview – remains so, he wasn’t prepared to let his clients lose the roofs over their heads.

The litigation dramatically ran out of puff in 1997 when it became perfectly clear Irwin Mitchell’s clients would be made homeless by the costs of the action. Leigh Day and Irwin Mitchell were forced to sign up to an unprecedented decade-long amnesty, throughout which they promised to hold legal fire.

Having passed this 10-year milestone, Day reckons he has just been approached by a prospective anti-tobacco client. Although he says that particular case is not strong enough, he adds: ‘I am going to do it, though. I am determined not to let the thing lie.’

What about an individual’s personal responsibility for their own health risks? ‘I [would] totally accept that, if the court was going to say in an individual case: "You take 50% of the responsibility for what you did and the tobacco company takes 50%",’ he replies. ‘However, what I feel is totally wrong is the idea that a company that has made zillions out of the misery of folk shouldn’t bear some responsibility.’

This combativeness characterised Day’s formative years in the profession. He completed his articles at a West End of London City-oriented firm, but he cut his litigating teeth in the early 1980s at the prominent human rights firm Bindman & Partners. His path to partnership was frustrated, as Day tells it, by internal politics and being ‘a bolshie git’. As an associate, he pushed for a management committee to run the firm. ‘Representatives from the staff met and decided that the lowest paid were being paid pretty poorly,’ he recalls. ‘I had a mandate from the staff to say that, if the partners did not agree to an increase, they would not be going in the next day.’

An attempt to instigate a strike was not taken as evidence of Day being partnership material. He was told that he was ‘on probation’ for a year, after which he decided to join Bindmans partner Sarah Leigh in setting up Leigh Day & Co in 1987. ‘If I was coming up through the ranks here, I’d be a total pain to deal with,’ he says. ‘I was very driven and always hated anybody telling me what to do. I always felt that I would rather live and die by my own decisions.’

The point about Leigh Day, as its senior partner explains it, was to create a legal practice to allow for individualism. Day claims his firm is well-placed to take on the kind of litigation that individual lawyers feel passionate about – representing the victims of environmental pollution on the Ivory Coast, Japanese prisoners of war, dying smokers or Iraqis taking on the British Army – but that their firms won’t touch for fear of being clobbered by costs.

Leigh Day has made a specialism out of David and Goliath legal actions. There have been some impressive wins, but ‘David’ has also had to endure the occasional thumping such as the tobacco action (which cost the firm £2.5m) and the failed action against contraceptive pill manufacturers.

But taking risks is clearly what drives Day on. He recalls acting at Bindmans for residents who lived around the Sellafield nuclear plant, including a family who lived in the most radioactive house in western Europe: ’You really need a firm with the resources to take on multinationals such as British Nuclear Fuels. It would just be me and one counsel, and they would have 10 or 12 lawyers, with a massive team of experts behind them.’ He argues that it is ‘difficult to break the mould’ in a traditional firm with numerous equal-sized departments, where an in-built conservatism prevents a firm backing riskier litigation.

Most recently, Day has been working with the campaigning lawyer Phil Shiner, representing Iraqi civilians suing the British Army. At the beginning of the summer, the Ministry of Defence agreed to pay out £2.83m in compensation to the family of Baha Mousa, who died after being beaten by British troops in Iraq, as well as nine other men who were detained and interrogated. Mousa’s body was found to have more than 93 injuries. His father told the Daily Telegraph at the time that it was ‘agonising to lose a son and know that neither me nor his children will see him again. We have had some sort of help through the compensation. It will not replace our lost son but it will secure a good future for his children. The British Army is a great army but it is not without its spoiled people’.

Day explains that the interrogation techniques used on the Iraqi civilians were prohibited by Edward Heath’s government in 1972, after the European Court of Human Rights condemned their use in Northern Ireland. His clients had ‘been through hell over the last few years’ and the settlement would go ‘some way to enabling them to have some semblance of a decent future life’, he says.

‘Two days before the mediation they were so depressed and down,’ Day continues. ‘Afterwards they were totally different people. It was as if a weight had been removed from their shoulders. The money was important, but as much as anything it was the apology that had been given during the mediation that counted.’

Lieutenant General Freddie Viggers, the army’s adjutant, apologised for the ‘appalling treatment’ they suffered at the hands of the British army. ‘The appalling behaviour of British soldiers made us feel disgusted,’ he said. Day describes it as ‘the most heartfelt apology that I had ever heard’. He adds: ‘Whatever the criticisms I have of the British Army – which are many – the way they dealt with that mediation was first-class. At long last our clients felt that justice was being done.’

The Mousa case is one of three Iraqi-related actions that Day and Shiner are involved in. They have just issued proceedings against the MoD over as many as 12 cases of alleged abuse of Iraqis at Camp Breadbasket, near Basra, in 2003.

What does Day say to those critics who argue that such legal actions are undermining the difficult work our troops do in Iraq? ‘We want to have an army that is the best in the world; but having an army that is the best in the world means, when incidents like this happen, they are properly and vigorously reviewed and properly prosecuted. Otherwise what sort of army do we have?’ he replies. ‘These aren’t the sort of things that we want brushed under the carpet. I am proud of my country, but part of that pride is having a system that recognises mistakes and ensures that justice is brought, whoever it may be.’

The firm has made its reputation heading massive group actions, such as acting for South African asbestos victims in their landmark legal action against the UK-based Cape Plc, Kenyans in cases against the British Army involving uncleared bombs, or Columbian farmers in compensation claims against BP over problems after an oil pipeline was built across their land. A former Greenpeace chairman, Day is currently involved in a massive multi-party action on behalf of injured victims and the families of those killed in a toxic waste disaster in the Ivory Coast city of Abidjan.

In August 2006, a ship chartered by the London-based arm of the shipping giant Trafigura unloaded a toxic waste shipment in Abidjan. Previously, there had been a dispute in Amsterdam over the high cost of disposing of the ship’s toxic cargo. Once in Abidjan, Trafigura contracted a local company, Tommy, to dispose of the waste. Trafigura says it contracted Tommy in good faith, but Tommy dumped hundreds of tonnes of the toxic waste in open-air sites and into the city’s waterways. ‘There were 18 dump sites across the city,’ Day explains. ‘More than 100,000 people ended up being injured and 15 of them died. We now have 20,000 clients and that will go up to 30,000 by the end of the year.’ On 23 October, Tommy’s head man was sentenced to 20 years in jail. The shipping agent involved received five years. Trafigura maintains that the material cannot have led to the deaths and widespread injuries alleged.

Leigh Day was also involved in the failed UK Vioxx litigation. At the end of last year the drug’s manufacturer, Merck, announced plans to pay more than $4.85bn to those US alleged victims of the anti-inflammatory drug who claim to have suffered heart attacks and strokes. It was reckoned to be the biggest settlement of its kind.

UK claimants represented by Leigh Day (and Irwin Mitchell) had taken their legal action to the manufacturer’s backyard in New Jersey in an attempt to bypass the UK courts after having been denied legal aid. There was a bitter exchange between the Legal Services Commission (LSC) and Day at the end of 2005, with the LSC claiming that the claimant legal team was not forthcoming about costs. The lawyer accused the LSC of ‘bloody-mindedness’ and the LSC responded by saying that it was not in the business of ‘writing blank cheques’. The New Jersey court ruled against the UK claimants towards the end of 2006.

Day took a pessimistic view of the failure of the Vioxx action at the time, saying it sounded the death knell of complex product liability action. ‘I cannot remember the last success there has been in the drugs field,’ he said then. ‘Maybe Myodil during the 1990s, but you could count them on the fingers of one hand.’ He was referring to the £7m settlement in 1995 on behalf of over 400 people suing Glaxo, claiming back pain was the result of spinal injections of the dye Myodil during medical scans.

These days, mere mention of the LSC tends to provoke a fairly extreme response in the man: ‘I shudder even at the mention of the words legal aid,’ he has said. Day is an advocate of ‘no win, no fee’, though. ‘If you had asked me five years ago, I would have said that there was no way that you could run a group legal claim without legal aid,’ he says. ‘But actually it has been the making of the firm because I no longer have to deal with the bureaucrats of Red Lion Street.’

In the Ivory Coast litigation, the firm was instructed in November 2006 and has a trial date for October 2009. ‘That is less than three years from first being instructed, and there are 30,000 clients in my group. If I was applying for legal aid I would still be arguing with the LSC about the strength of the case. How many cases have the Legal Services Commission funded that never even get anywhere before trial?

‘You have to be prepared to take some risks – some big risks – but the advantage is that it is speedy,’ says Day. ‘Our group action system is a really good one and I stand by it. By choosing the cases carefully, you can build up the treasure chest to take on more cases.’

So, is he still prepared to put the firm on the line? ‘Yes, absolutely. That’s who we are,’ he replies.

Surely there must be nervous lawyers at the firm who just want a quiet life? Day laughs, and says: ‘The work is fabulous here. The moment we refuse to take risks is the moment I’d give up. The moment my partners approach me and say "Forget it" is the moment I walk away.’

Tobacco companies, be warned.

Jon Robins is a freelance journalist