What's a man like Derek Nally - former garda sergeant, founder of Victim Support, candidate for the Presidency, supplier of security systems to the elderly - doing in the murky world of private investigation?

The answer, according to the man himself, is simple enough: there is nothing sleazy about the investigation business, and the corporate sector is beginning to wake up to the benefits of the service he and others provide.

"The whole private investigation business is becoming much more acceptable. It's a normal business like any other and has been part and parcel of corporate America for years."

Although not one for blowing his own trumpet, he is not given to false modesty either and acknowledges his personal role in bringing that change in image about. "People know me and that helps. A lot of my business comes about through personal contacts."

If people don't know him, they feel like they do. He has a what-you-see-is-what-you-get personality, and after two hours in his company you have the impression that the private investigation business would be obsolete if everyone was like him. No question is dodged and pauses for reflection are rare.

But he knows where to draw the line: "Confidentiality is the most important thing in this business. You must keep everything strictly confidential, and if a client ever heard you had been speaking about their business, well that's the start of the slippery slope."

As managing director of the Securway Group, he is head of a business which doubled its turnover to £1.4 million (€1.78 million) in the year ending May 1999 and is on course to increase that by a further 50 per cent - to £2 million - this year.

He attributes such rapid growth to the buoyant economy and the growing awareness and acceptance of the investigation business.

Following his retirement from the Garda Siochana in 1987 after 30 years' service, he founded International Investigations Ireland - now part of the Securway Group - which was mainly concerned with carrying out surveillance on people who had made personal injury claims.

Nally and Associates, which provides a background investigations and document service, was established later. Five years ago, Securway was set up, largely as a result of clients asking for a security service after an investigation had been completed.

The group employs 84 and has offices in Dublin, Belfast and Bunclody, Co Wexford, where Mr Nally lives. He and his wife Joan, who runs Nally and Associates, have two daughters who both live abroad.

There is no such thing, he says, as a typical request from a client. Jobs taken on by the group range from "pre-sue checks" to investigations of internal company irregularities to the provision of security cameras. The group has also provided surveillance of "litter blackspots" for a number of local authorities, which use the resultant evidence to prosecute offenders.

"Every job is an individual job with its own peculiarities, and it's not until you get the ingredients of the case that you can sit down and tackle what the best way of doing it is."

He also runs Emergency Response, which is not part of the Securway group, and has a turnover of "between £250,000 and £500,000". He insists he is not, however, making a large profit from the 14,000 mainly elderly subscribers who use the personal alarm system.

With a staff of 13 providing a 24-hour, 365-day security response service, the costs involved are high. "We're the Ryanair of the security business - but without the profits," he says.

At Securway, he has a team of senior executives who get on with their own jobs. "I wouldn't know everything that's going on [in the company]. Sometimes I'd meet someone and they'd say `you're doing that job for us' and I'd be struggling, to be honest.

"But I keep an overall view of the financial side of it and the PR side and I do become personally involved in a small number of important cases, or when a client asks for me specifically to deal with something."

Delegating is more necessary than ever because as current president of the Council of International Investigators, he is frequently abroad. He took on the role because, he frankly admits: "I'm a sucker for saying `yes' when I shouldn't. I really should say `no' more often." The position is time-consuming, but does have its advantages. "There are very few places in the world now that I wouldn't have a contact. If a couple came to me and said they had a problem, such as a daughter missing in Lima, they know I'd be able to get them someone who was professional and reliable and wouldn't cost an arm and a leg."

Becoming president of the council, in any event, was merely the continuation of a lifelong pattern which has seen him rise through the ranks of whatever activity he turned his hand to.

Having co-founded a youth club in Bunclody in 1965, he went on to become chairman of what is now the National Youth Federation. He also served as general secretary of the Association of Garda Sergeants and Inspectors for 10 years.

"I suppose whatever I've got involved in I've had an interest in educating myself about what was going on outside of the immediate organisation. I'm a great believer in looking at the wider parameters and seeing what ideas can be brought home."

He is perhaps best known as the honorary life president of Victim Support, which he founded in 1983 and now has 20 full-time staff and 500 volunteers. He no longer has an executive role, but still attends functions as the public face of the organisation. There is not much time, then, for relaxation, but he intends to change that. Now 63, he plans to work for "two or three more years" before retiring to devote more time to his "passion and sole interest" outside work - national hunt horse racing.

"My ambition would be to own the leg of a horse if I could put enough money together." But will he really be able to turn his back on the work when the time comes?

"Oh absolutely, no problem there at all. I'm quite good at switching off." He and Joan take holidays in the sun every year "and when I close the door of the office that's it. I know I have staff who are quite capable of doing the job and while I'm away I don't think about it at all".

His failed bid for the Presidency in 1997 and the recrimination it brought within his own camp is well documented, yet he has no regrets about running and no problem discussing it two years later.

"I met a lot of very nice people and got a lot of support from people I had never met in my life. We also got huge financial support. If only we'd got a vote for every pound we got we'd have been much further up the field!"