Cahill was educated at Rockwell College, Cashel, South Tipperary and the Royal Military Academy Sandhurst. He was commissioned by HM Queen Elizabeth II in July 1965 and served as a platoon commander in Aden, Bahrain and Northern Ireland, leaving the army in 1968. He attended the (New) University of Ulster as a mature student from 1972 to 1975. He was Chairman of the Union and left with an honours degree (BA) in English Literature. At university he won (with Michael Hughes) the Irish Times National Debating Championship. His operetta (translator Aine Ní Currain) Dado won the main award at three of the four provincial drama festivals and opened the national drama festival in Dublin in 1975.

Cahill worked as a systems analyst at Farrington Data, Rank Xerox, Glaxo Ltd, Gulf Oil UK and Singer & Friedlander merchant bank. He finished his professional career in computers as a project manager at ICL.

In 1979 he became a full time journalist. Starting with Computer Weekly as International and Finance Editor, then went to Computer News as Deputy Editor. He was associated with various other computer magazines including Nikkei Computer and Asia Computer Monthly. In 1988 he moved to work on the Sunday Times Rich List with Dr Philip Beresford and stayed at the ST in various capacities, including a major stint on Insight, until 1991.

He currently writes for FACTA magazine in Tokyo and is Bureau Chief at the Global & Western News Bureau in Exeter, Devon.

Cahill has been a part time Research Assistant to Paddy Ashdown in the British House of Commons. He also worked for the Chairman of the Parliamentary All Party Human Rights Committee in the House of Lords.

He has advised many notable politicians including:

• Hon Richard Burke former European Commission Vice President
• Gordon Brown on offshore taxation in 1991
• Robin Cook on the Scott Inquiry in 1996.

Airey Neave assassination conspiracy theory

Kevin Cahill claimed that, prior to his assassination in 1979, Conservative MP Airey Neave was on the verge of a massive overhaul of the security services, possibly involving a merger of MI5 and MI6 and arising from his belief in corruption in the security services. Cahill suggests a link between Neave's murder and Sir Christopher Sykes' murder and the attempted murder of Christopher Tugendhat in December 1980. Cahill claims that Neave would have been head of the combined security services with Sykes and Tugendhat as his deputies, with Sykes responsible for foreign operations and Tugendhat responsible for home operations.

Cahill claims to have had a conversation with Neave on St. Patrick's Day 1979 in the foyer of the Irish embassy in London. Cahill had left a party and was waiting for a taxi. He saw Neave in the room and introduced himself to him as an admirer. Cahill claims that Neave was inebriated and responded "quite out of the blue" by saying "There are going to be changes here, big changes, soon. There is going to be cleaning of the stables...There has been serious corruption." Neave then said that there was "no use playing games. We have to win...We will win when the [corruption] is sorted out. Count on that." Cahill found Neave's remarks surprising because he seemed internally preoccupied with the UK, with his Northern Ireland brief "almost a sideline". Cahill also thought that Neave's mention of corruption meant Soviet penetration.

Whilst working in the House of Commons as Paddy Ashdown's research assistant Cahill claims to have had around six conversations with the security staff there. The most frequent remark was that "everyone knew" the story behind Neave's death but that no one could talk about it in detail because it would have been too dangerous. Cahill claims they did not believe INLA murdered Neave but that it was an "inside job".

Cahill concluded that Neave was murdered by the security services; MI6 agents working with the CIA because Neave sought to prosecute senior figures in the intelligence establishment for corruption.

He has written several books on differing topics:

Technology and businessThe Principles of Business Systems (1970)Trade Wars (1987)

Land and propertyWho Owns Britain (2001)Who Owns The World (2006)

In his 2006 book, Who Owns the World: The Hidden Facts Behind Landownership, Kevin Cahill notes that Queen Elizabeth II is the legal owner of one sixth of the land on the Earth's surface, more than any other individual or nation. This amounts to a total of 6.6 billion acres (27 million km²) in 32 countries. For those unfamiliar with royalty the Crown is never separate from the individual who holds it but is as one with them. Mrs Elizabeth Mountbatten Windsor is the Crown while she is Queen, and she loses neither her personality nor her individuality while she is monarch. In all territories owned by the Crown, including Australia, New Zealand and the United Kingdom, the governments of those countries do not own the land of the country, but may and frequently do administer it on behalf of its owner, HM Elizabeth II. More significantly all forms of land possession in those territories are based, formally and in law, on the Crown's superior ownership. This is why the Land Registry in places like the United Kingdom, Canada and Australia cannot register land ownership, only tenure. This is also why freehold and leasehold are defined in law as forms of tenure, not ownership.

Cahill also noted that of all the countries in the world that he looked at over a several year period, the only major country in which ownership of land was clearly defined as belonging to the citizens who had paid for it was the United States This is sometimes called 'allodial' ownership but is a changed meaning of that word. Originally 'allodial' meant land that could not be bought or sold or have a debt attached to it. Countries which have a form of direct ownership, even if it is not clear in their respective constitutions, include Germany, Switzerland, France, possibly Spain and in the future, Russia.In the United States the Federal Government owns about one third of the land of the country. But it does so as a landowner on a legal par with any other landowner and without a superior right to any land other than that endorsed on deeds as the property of the Federal Government. As a government the Federal Authorities and other public bodies do possess the right, sometimes called 'eminent domain', to acquire privately owned land for public purposes.

In the October 2001 Business Age Magazine p18 Kevin Cahill wrote about the economy of Cornwall. In The Killing of Cornwall, he notes that the London Treasury extracts £1.95 billion in taxes out of Cornwall's GDP of £3.6 billion. The Treasury returns less than £1.65 billion, so there is a net loss to Cornwall of 300 million pounds, where the total earnings figure is 24% below the national average. Cornwall is getting poorer by the day, and Cahill offers this explanation: One very simple and easily provable answer is because the Government in London is raping Cornwall fiscally. The fiscal deficit of over £300 million all but completely explains the increasing pace of impoverishment in Cornwall. Cahill concludes his Business Age article with the lament that Cornwall will not recover until the gap between the tax take and the exchequer give is at least neutralised and better still, reversed. Business Age Magazine ceased publication in 2002.