He grew up on the Caribbean islands of Trinidad and Tobago, where his father was Archdeacon. Money was scarce but fish were plentiful, so John and his brother were often sent off by their mother to the reef, with orders for lobster or snapper. At 14 he bought an old fishing boat and started hunting for bigger game. As a young man he would often dive 50 feet or more without an aqualung, holding his breath for several minutes to harpoon his prey. His record catch was a 400lb grouper. On one occasion a school of sharks came to share his catch while he was still underwater; he escaped by remaining completely still and allowing himself to be washed up painfully on the coral reef.
School was a pleasantly intermittent feature of his childhood and he did not read until he was eight. Nevertheless he won the Island Scholarship to Cambridge from Lodge School, Barbados, and went up to Queens' College in 1949, to read Natural Sciences.
At Cambridge he was a boxing Blue and coxed and swam for his college. He discovered rock climbing almost by accident after he impressed members of the Cambridge University Mountaineering Club with his natural skill at climbing round the edges of a room during a party. On the basis of that demonstration he joined the club and proved equally agile at weekend meets on the gritstone outcrops of Derbyshire. However, it was only in his final year, in June 1952, that his full talent was realised.
His fellow members Ted Wrangham and George Band had introduced him to some of the classic climbs of North Wales, including the Girdle Traverse of the West Buttress of the Clogwyn du'r Arddu, usually abbreviated to a more manageable "Cloggy". The huge, slanting, overlapping slabs of this magnificent cliff near the Snowdon Railway gripped Streetly's imagination and he determined to tackle a red-streaked slab on the right-hand side of the cliff which had already defeated several attempts.
The first moves were quite straightforward but Streetly soon found himself on smooth rock with only the tiniest wrinkles for friction. The rock was also wet in places, so he took off his smooth plimsolls to climb in socks. When he did find holds, they frequently came off in his hands, one block weighing about 20lb. At one point he climbed a strip of grass, only to find it unpeeling from the rock - "rolling down from the top like a thin green carpet", as he described it in the CUMC journal.
And so it went on, with the rope clipped only to a few thin slings, draped on dubious flakes of rock and one token piton hammered into a shallow crack. After 200 feet he ran out of rope. His second, Ted Wrangham, was unable to follow, and Streetly had no earthly hope of reversing the slab. The only solution was to untie and, "after gazing wistfully at the white end of the rope slithering out of sight down the slab", continue alone, unroped, to the top of the cliff.
"Bloody Slab" is still given an Extreme grade of E3, 5b. Modern rock climbers, with all the benefits of sophisticated protection gear and special climbing shoes, will know what daring and panache is represented by that coded message and approach the route with cautious respect. In 1952, when activity on the cliff was dominated by a talented new generation of predominantly working-class climbers, spearheaded by the Mancunian plumbers Joe Brown and Don Whillans, this bold coup by a Cambridge undergraduate made a huge impression and Whillans, generally suspicious of university types, became a very good friend.
Back in Cambridge, Streetly and George Band concluded their final Trinity term with a dawn ascent of St John's Chapel, before heading for the Alps. There they made the first British guideless ascent of the North Ridge of the Dent Blanche, first climbed in 1928 by the local guide, Joseph Georges, with Dorothy Pilley Richards and her husband, the celebrated critic I.A. Richards.
George Band went on to join the 1953 Everest expedition. John Streetly returned to Trinidad to help support his mother and brother, following his father's early death in 1952. In 1957 he married Elisabeth Macfadyen and the responsibilities of bringing up a family compounded the need to limit his climbing activities. He worked on the oilfields in Trinidad, then for US Steel in Venezuela, then in 1960, with Hank Sylvester, founded Brisco - the British Scientific Company, specialising in support for offshore oil-rigs. He later sold the company to Booker McConnell.
Accounts of his career in the oil business abound with tales of daring, such as standing on his head on the top of a 200ft derrick for a bet and, this time in earnest, escaping from a burning rig by sliding hand over hand down one of the tethering steel hawsers. Just five feet four inches tall, he was a compact ball of energy.
During holidays he continued to climb when he could, joining John Kempe's party in 1956 to make the first ascent of Huagaruncho in the Peruvian Andes, reaching the 5,730-metre summit with Mike Westmacott. In 1959, in an astonishing piece of bravura, he flew to Britain and, at Don Whillans's invitation, hurried on immediately to Chamonix. Without any warm-up he went straight up to the Leschaux Glacier to start the Walker Spur on the Grandes Jorasses with Whillans, Hamish MacInnes and Les Brown. He led virtually every pitch on this 4,000ft route, which was then revered as one of the hardest climbs in the Alps. The only regret was that Gunn Clark and Robin Smith beat the party to the first British ascent by one day.
The following year Streetly visited the Himalaya as a member of the team which made the first ascent of Everest's north peak, Nuptse. Although astounding fellow members with his tree-climbing prowess during the approach, on the mountain itself he was unwell, showing the first hints of the arthritis which would later cripple him.
During the southern summer of 1962-63 he joined Barrie Page's expedition to the stunning, monolithic Central Tower of Paine, in Patagonia. Always very much the team player, he was happy, having led some of the initial pitches, to work in support of Don Whillans and Chris Bonington, at one point removing fixed ropes below them to thwart a rival Italian party hell-bent on making the first ascent. The Britons won the race. Later expeditions included several adventures in the jungles of Guyana, climbing, fishing and collecting botanical samples for Kew and, in 1971, making the first attempt on the great overhanging prow of Roraima, later regaling London pub audiences with surreal tales of lashing together immense tree trunks to gain a foothold on the impending wall.
John Streetly helped organise the expedition which finally climbed the Roraima prow by more conventional methods in 1973, but he himself had to drop out of the team because of a knee injury. This proved to be the end of his climbing career and, as arthritis took hold, he sought solace in his skill as a fly fisherman. With the development of the North Sea gas and oilfields, Brisco was by now also operating in Britain and in 1982 John and Elisabeth Streetly settled in Devon. From the open door of their sitting room, the fisherman was virtually able to cast straight into the trout stream at the bottom of the garden.
John Streetly was admired for his irrepressible energy, his courage and his huge range of enthusiasms, but it was his climbs which made the most public impression. The late Don Whillans, not a man to give compliments lightly, wrote after first climbing with him in 1952:
With the possible exception of Joe Brown, John was the best rock climber I'd ever climbed with . . . although he could climb as delicately as a fly, moving fluently over seemingly holdless rock, he could also overcome with ease problems requiring sheer physical strength.
Geoffrey John Streetly, mountaineer, sportsman and businessman: born Swindon, Wiltshire 2 August 1928; married 1957 Elisabeth Macfadyen (one son, four daughters); died Exeter 3 December 1999.Reuse content