FOR some firm believers in Welsh independence, John Jenkins is one of the most iconic figures in the Principality's recent history. Yet for many he remains a divisive figure, who for a time was one of Britain's most wanted men and one who was sentenced to 10 years imprisonment for a sustained campaign of terrorism, which 50 years ago even threatened the lives of the Royal family.

Jenkins, now in his 80s living a quiet life in Wrexham, has always been guarded about his role in masterminding a four-year bombing operation as the head of MAC - Mudiad Amddiffyn Cymru, or the Movement for the Defence of Wales.

But now, a new book, John Jenkins - The Reluctant Revolutionary? written by Dr Wynn Thomas, will finally open the door on one of the most fascinating periods of Welsh history and one of the most intriguing characters involved.

"I have loved all history with a passion since very early childhood," explains Dr Thomas, who was born in Llandrindod in 1967. "But if one event inspired my interest in Welsh militancy, and why I resolved to approach historical writing in an impartial and balanced manner, it was when in my early 20s, I learned the water pipeline from Cwm Elan to Birmingham, at a point no more than five miles from my family home in Llandrindod, had been targeted by Welsh militants in 1952.

"I reacted with happy surprise, thinking how great it was that the boys were standing up for Wales, only for my mother to tear a strip off me because my dad, at the time I was born was a young Police Constable and he had to routinely patrol the Radnorshire section of the pipeline in search of explosive devices. She explained she had been worried sick for his safety and the thought that had he been injured, or worse, she might have had to bring up three young boys on her own.

"It brought me up sharply and made me realise how it could have massively affected my life. I decided that when I wrote about history I would do it in a very nuanced and considered way - history affects people's lives - and it's what I've tried to do ever since."

Cardiff-born Jenkins was a non-commissioned officer in the British Army's Royal Army Medical Corps, when in 1963, he effectively took over the leadership of MAC. Working undercover, Jenkins began operating a sophisticated cell system of Welsh operatives with a system of safe houses, dead letter boxes, dumps, sympathisers, informers and activists. The group's activities primarily targeted infrastructure carrying water to Liverpool and was set up in response to the flooding of the Afon Tryweryn valley and the flooding of the village of Capel Celyn to provide water for Merseyside.

"John is extremely intelligent and very charismatic," recalls Dr Thomas, whose book has been officially authorised by Jenkins. "He has been incredibly forthcoming but it has taken a long time to get there. I really wanted to get to the nitty gritty of both the campaign and this man's character - what fuelled this man to do what he did?

"It all came from the anger about the flooding of Afon Tryweryn," he continues. "Thirty six Welsh MPs opposed the Bill but it was passed anyway and people like John felt they'd exercised their democratic opposition and the voice of Wales had been ignored, so what else could they do other than sustained bombing campaign?"

Under Jenkins' leadership, MAC was suspected by British police to have been behind the bombing of the Clywedog dam construction site in 1966. In 1967 a pipe carrying water from Lake Vyrnwy to Liverpool was blown up. Later the same year MAC exploded a bomb at the Temple of Peace and Health in Cardiff's civic centre, close to a venue which was to be used for a conference to discuss the Investiture of Prince Charles as Prince of Wales. In 1968 a tax office in Cardiff was blown up, followed the same year by the Welsh Office building in the same city, then another water pipe at Helsby, Cheshire. In April 1969 a tax office in Chester was the next target. On June 30, 1969, tragedy hit the campaign when the evening before the Investiture, two members of MAC, Alwyn Jones and George Taylor, were killed when a bomb they had been placing near government offices exploded prematurely.

"There were 20 explosions over two years and John has always said to me they were targeting places like tax offices and pipelines which they saw as easy targets," says Dr Thomas. "John would stop off in pubs on the way back from an operation and would overhear people talking about the bombings and they weren't outraged about what they were doing. There was a certain amount of acquiescent support for what was going on but in no way do I want to glorify the campaign. It's just that if you sweep something like this under the carpet it develops a sort of mysticism and romance."

On the day of the Investiture, two other bombs were planted in Caernarfon, one in the local police constable's garden which exploded as the 21-gun salute was fired. Another was planted in an iron forge near the castle but failed to go off. The final bomb was placed on Llandudno Pier and was designed to stop the Royal Yacht Britannia from docking - this too failed to explode. Tragically, five days after the Investiture, Ian Cox, 11, of Chalfont St Giles, Buckinghamshire, was playing behind a shop while on holiday with his family when he found what he thought was a football, but was in fact the second bomb which went off when he kicked, causing him to lose his leg.

"Poor Ian Cox was very badly injured and that can never be justified, no matter what the political cause," says Dr Thomas. "It's one of the reasons I wanted to tackle the subject because I don't think it has been really analysed before and if it has it has been written about as if it was a Boy's Own Adventure, but it is much more serious than that."

In November 1969, following a tip-off, Jenkins was arrested, and in April 1970 he was convicted of eight offences involving explosives and sentenced to 10 years' imprisonment. In a BBC2 interview shown on July 4, 2009, Jenkins repeated his assertion the bombs were never planted nor timed to hurt people, but just to disrupt the ceremony.

"There is a certain degree of courage needed to undertake a bombing campaign of this nature," says Dr Thomas. "It is certainly not the right way to go about things, but I can recognise the courage and his desire for the voice of the nation to be heard."

Five decades on from the Investiture, the number of Welsh speakers has surged to 874,700 - up from 726,600 in 2008, according to the Office of National Statistics and there is a very real risk the United Kingdom could split, leaving a devolved Wales once again considering its independence. Meanwhile, patriotic murals bearing the slogan Cofiwch Dryweryn (Remember Tryweryn) continue to appear all over the country.

"John is convinced the bombing campaign was an essential part of Wales' devolution journey and led to the creation of the Welsh Assembly," adds Dr Thomas. "In terms of his legacy I'm not sure. How will future generations regard John Jenkins and could he be held in the same regard as Owain Glyndwr for instance and be one of Wales most famous freedom fighters? Maybe he will be dismissed as some feckless deluded cynic.

"What I do hope is John's story serves as a warning to our political representatives - if people feel ignored, forgotten and impotent, they will react. I'm also saying this isn't the right way to go about it because invariably there will be death, injuries, and lives will be destroyed. It's a warning to everybody."

John Jenkins - The Reluctant Revolutionary? - Authorised Biography of the Mastermind Behind the Sixties Welsh Bombing Campaign by Dr Wyn Thomas is published on June 22 by Y Lolfa. The book will be launched at 4pm on Saturday, June 22 at Waterstones in Wrexham in the company of the author and John Jenkins. The Cambria Band that John co-founded will provide entertainment. The book launch will be followed by drinks at Saith Seren from 5pm onwards.