With a guide, a map and lots of tea breaks, Simon Calder retraces the steps of Felice Benuzzi, a PoW who escaped to climb Mount Kenya – then snuck back into camp.

Three in the morning is a tough time to start a walk, especially if it involves clambering over scree, snow and ice to gain half-a-mile of vertical altitude. But you need to begin at "stupid o'clock" if you are to tackle the final stages of Shandy Mountain. This is the uncharitable title given to Mount Kenya by those who have conquered Kilimanjaro. Africa's highest mountain, known as Kili or "the Hill" by braggarts, is located fractionally south of the Kenyan border in Tanzania. It towers over the continent at 5,895m – almost a kilometre further from the centre of the earth than the target of my climb.

To besmirch further the efforts of the trekker opting to climb Africa's second-highest mountain: Mount Kenya, a decaying volcano straddling the Equator, has not one but three peaks. No prizes for guessing which I am aiming for: yes, the easiest of the three, the 4,985m Point Lenana, the so-called "trekkers' peak", for which almost no previous experience is required; Sir Edmund Hillary need not apply. The two taller points are, well, points: shafts of rock that soar scarily skywards. These are "technical climbs", requiring of equipment such as ice axes and ropes, plus expertise. To tackle Nelion (5,188m) or Batian (just 11m higher) you need to be a proper mountaineer – like Felice Benuzzi, author of the most compelling book in the considerable repertoire of mountain stories: No Picnic on Mount Kenya.

Despite the title, this is a book about a series of picnics on Mount Kenya (and much more besides) – although, in that strangest of times during which Signor Benuzzi made his climb, the supplies became depressingly depleted as the atmosphere rarefied. The effect of the Second World War had rippled far beyond Europe. In East Africa, Italians were rounded up by the British and incarcerated in camps. Felice Benuzzi, born in Austria but educated in Rome, was among them. He was deported from Ethiopia, where he worked, to PoW Camp 354 at Nanyuki, about 100 miles north of Nairobi. The 10,000 prisoners, he later wrote, were "an assortment of all ages and trades... old and young, sick and healthy, crazy and sensible". Benuzzi ticked the box marked "crazy".