John McNeil was one of the co-founders of Logica, Britain's first major computer software company, and was one of the leading lights in the early days of UK computing. But he was also a writer, with four books and a string of TV screenplay credits to his name, as well as being a political activist with great energy.

He was born in Oxford in 1939 and he grew up in London, passing through grammar school with a reputation for academic brilliance and student insurrection. Despite eventual expulsion for one too many mischievous incidents, he went on to secure a place at Imperial College, graduating in 1961 with first class honours in aeronautical engineering.

Noting with chagrin the British aircraft industry's obsession with Concorde instead

of the larger and more practical jumbo jet, John forfeited an aerospace career and followed one of his maths professors into a brand new industry: computing. He joined Scicon, a US company establishing itself in the UK at the time, and quickly progressed from programmer to consultant to divisional manager and eventually to assistant general manager, at the age of just 29.

Along the way, he did such a sterling job of helping BP model the oil business in the Middle East that they bought the company.

In 1969, John and four others left Scicon to found Logica, one of the success stories of British computing. From its initial, tiny number of staff it grew into an international plc, with thousands of staff and projects underway in every significant area of commerce and government. John was at the cutting edge, leading teams that developed the first UK bank cash dispenser, the first British word-processing system, the British Gas national grid control system and other ventures. He also set up its two overseas branches, in Australia and

the Netherlands.

He left Logica in 1977 and joined Data Logic, heading marketing and charged with the establishment of a consultancy division. Further major projects followed, including IT and communications advice to the police, wargaming with the MoD and the development of an IT strategy for the Post Office.

But while waiting to take up his post at Data Logic, John found a new diversion - writing, and he penned a novel, The Consultant, in 1978. One of the earliest novels on computer crime, it was turned into a major television series by

the BBC, and it marked the beginning of John McNeil's emergence as an author.

The Consultant was the first of four books, with Spy Game, Little Brother and the Hoolet all following between 1978 and 1992. Writing and business

co-existed for some of the time, but eventually the creativity drowned out commerce and he became a full-time writer, branching into screenplays and writing Crossfire, a BBC drama about the IRA, and Shoot to Kill, in Northern Ireland. He also became chairman of the Writers Guild of Great Britain.

John still found time for his other great love, politics. Always a socialist, he was an active Labour supporter in London in the sixties, but for the past 15 years, had been a committed member of the SNP, serving as local branch chairman in Helensburgh.

Beyond work he had a passion for art and art deco, eventually combining the two with his ownership of a listed 1930s house in Scotland that was

big enough to display his collection of modern artworks. While this sounds like a neat solution, Greenpark actually required 12 years of renovation work, demanding that John become a plasterer, glazier, roofer, plumber and electrician in the process. Thankfully McNeil's mental practicality was always matched by the skill of his hands, and he

would think nothing of leafing through a period book on plumbing in the morning and then fitting a sink to the wall that afternoon. The house is now rightly gaining a reputation as one of Scotland's finest art deco private homes - all as a result of this painstaking restoration.

John McNeil returned to business in 1992, joining a small energy conservation company, Heatwise, in Dumbarton. Renaming it Solas, meaning ''hope'' in Gaelic, he turned it from a struggling venture into a thriving success, winning a host of awards for business excellence.

Solas was a community business; it was a registered charity that worked specifically with the poor and elderly. It had no shareholders and any profit went straight back into the business. He believed Solas showed the future, an unexportable source of local employment with low costs and high social benefits, and championed this message to anyone who would listen. The success of the company has gone a long way to proving his ideals.

John McNeil was also a regular writer to The Herald, his letters appearing frequently in print. He held a great many strong views on a wide range of issues but, whatever the matter, his letters were always eloquent, thoroughly principled and elegantly simple.

This Renaissance man, with irons in a hundred and one fires, died far too early, but those who knew him would nevertheless probably agree that they were lucky to have had his company for as long as they did.

He is survived by wife, Mary and son, Rufus.

John McNeil, engineer and writer; born December 16, 1939, died October 22, 2004.