Ian Hamilton Finlay, who died at the age of 80 on 27 March 2006, was one of the most influential British artists of the 20th century. His output was marked by intense political controversy.

His early works, poetry and short stories, developed in the early 1960s into an engagement with the world of concrete poetry, an artistic form first popularised in Brazil, though Finlay's variant was self-generated and contemporaneous (like that of his Scots compatriot Edwin Morgan, whose 1966 poem observed of his friend "you give the pleasure / of made things"). Some of this was exhibited at an international exhibition of concrete poetry at the Brighton festival in 1967, where I first saw it, and it made an immediate impact then – principally one of delight.

In Finlay's own creations, word puns, elegant typography, and a printmaking technique based on picture-book-style images and words created a childlike marvel at the connection between words and things. The tension between pictures and labels, images and text, was also at the heart of linguistic philosophy in the 20th century, and Finlay nearly always described himself as a philosopher-poet rather than an artist. For Finlay and other concrete poets, the alphabet represented a collection of signs (and variable sounds and meanings) of infinite wonder: they were in effect modern abecedarians.

His subsequent adherence to classicism in his sculptural work was owed, he said, to his collaboration with engravers and letter-cutters – who nearly always worked in Roman type. A growing interest in the place of inscription – especially in the city or the landscape, often reworking the motifs embodied in Poussin's paintings of Et in Arcadia Ego – made him the one British artist admired and emulated throughout Europe in modern landscape design.

One such work, completed in 1999, was Finlay's collaboration with Dutch artist Krijn Giezen, to celebrate the cleaning up of the Haagse Beek, which brings water from the sea to the Mauritshuis on the Hofvijver in the centre of The Hague. At its point of entry Finlay designed a brick arch and water-funnel, above which he placed a plaque proclaiming the enduring sentiment ET IN ARCADIA EGO. In fact the artistic intervention itself is discreet and low-key almost to the point of invisibility. Nevertheless it raised a good deal of public interest in the story of the river, as well as on the function of inscription in the city, leading to a wonderful essay on the role played by monuments and inscriptions in Dutch civic culture by landscape designer Erik de Jong.

Ian Hamilton Finlay photographed by Murdo MacLeod

A youthful obsession with fishing-boats, dinghies, barges, sailing-ships – and their colours, construction and the typography and poetry of their names – continued throughout his life, and reflected his work at its most innocent. There is a lovely photograph of him at play with his children, as they sail a small handmade boat on the pond (The Temple Pool) at Little Sparta, the home and garden he established in lowland Scotland's Pentland Hills in the late 1960s. In Michael McNay's Guardian obituary, there is an equally touching portrait, by photographer Murdo MacLeod, of Finlay near the end of his life, sitting in his garden holding and surrounded by beautiful coloured model sailing-boats.

Finlay's graphic work was often published in small press editions, beautifully designed and printed. When the photographer Jason Orton and myself met the designer Steve Parker, who designed our book on the Essex landscape, 350 miles, we took with us a copy of Finlay's Reef-Points as a model. The world of small presses and craft-book production which he and other concrete poets espoused – a slow-burning fuse in the wider culture of signs and representations – seems a far cry from the instant celebrity of much Brit-Art, which possesses little afterlife.

A difficult fascination

Apart from an obsession with sailing craft, there were others too, some more difficult to understand. One was with the rhetoric and personality cults of the French revolution – figurative busts, axes, guillotines, beheadings, slogans, insignia – which showed an almost unhealthy preoccupation with the tensions between pity and terror, or of brutal ideological certitude embodied in exquisitely designed artistic forms. Art critic Tom Lubbock has aptly summarised this as embodying a "tragic conception of politics, where idealism and catastrophe are inextricable".

Finlay could not let go of the shock and awe implicit in the notion of Enlightenment, a kind of forced march into modernity. Here the tension between words and things becomes an unresolved contest between the horror of the subject-matter and the exquisite simplicity and even joy of the finished artwork. Of the many awards given to artists in recent years, one of the strangest must be the award of a bust of Saint-Just to Finlay by the French Communist Party in 1991. You do have to come to the work from some unusual angles.

At the same time, the love of model boats and toys – Finlay had been a keen toy-maker – became a fascination with model warplanes, tanks, machine-guns, grenades and finally the emblems and insignia of the Third Reich. Many people found this latter fascination difficult to come to terms with, and his reputation suffered as a result. This was something he wasn't really prepared to discuss, as he saw it as well within the bounds of artistic exploration. His interest in the machinery and insignia of ruthless militarism – which he may have felt underpinned even the most liberal of societies – clashed badly with the "make love, not war" ethos of much artistic endeavour in the second half of the last century.

The Sea's Leaves, 1990, Neon, glass & Perspex, Victoria Miro Gallery

In a 1996 interview with Nagy Rashwan at Finlay's house, Little Sparta, near Dunsyre, Lanarkshire – subsequently published in Jacket 15 (December 2001) – he spoke about this interest in classical and French revolutionary motifs (though not those of the Third Reich):

"… I don't feel a distance between me and the classical. To me it represents quite a natural language. Other languages could be natural too, but I don't feel outside the classical. It is clear that most people when they think about these things, their biggest experience is of a distance. I don't have that experience. I have often said that just as the French revolution, for instance, understood itself through antiquity, I think our time can be understood through the French revolution. It is quite a natural process to use other times to understand your own time. It offers a kind of dramatic possibility or something like that. Of course our time does not try to understand itself at all, unfortunately, but times have always understood themselves through other times which provide a means of dramatising the issues of the present."

I also went to interview Finlay in January that year, as I was then writing about new designs for parks in Europe, a topic on which his name was frequently invoked. The visit was made especially memorable – to me at least – by the fact that Little Sparta was entirely snowed in. I had to walk across several fields whose paths and ditches had been obliterated by snow – as was the garden of course – to reach the house, returning one foot at a time in total darkness. Finlay was thoughtful, serious and kind – but he used a vocabulary of politics and art that was entirely foreign to me then, though perhaps less so now. Central to this vocabulary was the notion of piety. There is a Christian sense of piety which is commonly understood, but Finlay meant something quite different.

Ken Worpole's writing on openDemocracy includes:

"Stockholm Woodland Cemetery"
(January 2003)

"Essex shores, Essex lives"
(September 2003)

"The world's first environmental blogger" (August 2005)

"Living on water" (December 2005)

"Aldo van Eyck, The Playgrounds and the City" (February 2006)

"Lido life" (March 2006)

As far as I could tell, for Finlay piety meant a submission to order: order of form, order of expression, order of society. His work often referred to the classical orders of architecture, and broken capitals and columns litter his designs and landscapes, so to speak. Then there is the order represented by typography, one of the most profound and historical forms of cultural expression, now used promiscuously and haphazardly to ever-decreasing effect. There is also the order embodied in mythology, emblems, insignia, signs and motifs, which once held the city and the social order together, but whose meanings have collapsed from within – thankfully some may say.

Even before his death, it was increasingly agreed that the garden at Little Sparta was his greatest work of art – it was certainly the most influential. Every single contemporary designed landscape anywhere in Europe, if not the world, has incorporated elements of Finlay's vision of a world made new by reference to the old. Formalism, inscription, the melding of the natural with the sculptural and the architectonic, are now everywhere back in favour. In his obituary in the Independent (subscription only), Tom Lubbock properly claims that Ian Hamilton Finlay has the right to be regarded as one of the most important artists of the last fifty years. Certainly his influence on landscape design and on matters of architectural inscription and memorialisation has been profound, and is likely to be lasting.