The lights go up to reveal a small boat. An elderly man bursts out from underneath its tarpaulin. Dishevelled and babbling, he appears like a Beckett character, talking to himself in breathless sentences at first as he creaks out of the boat and gets dressed, swigging his breakfast from a bottle.
Although he looks like a hobo, he is in fact Harry McNish, a man with a heroic past. In 1914, McNish was a carpenter and crew member on Ernest Shackleton’s Imperial Trans-Antarctic Expedition, which attempted to make the first land crossing of the southern continent.
He helped save the 28-strong crew when their ship, the Endurance, was crushed by ice. Now he is alone and infirm with hands that have gnarled up, living destitute on a New Zealand dockside in an abandoned boat.
The drama unfolds as McNish (Malcolm Rennie) begins seeing and speaking to the ghosts of his past parading before his whisky-soaked eyes. There is Shackleton himself and other crew members whose apparitions comfort or agitate him, including his old friend and fellow Scotsman, Thomas McLeod.
Rennie is a stunning actor who keeps our attention in a sometimes relentless monologue that takes us from the terror – and poetry – of the Antarctic ice to the character’s former wives, mistress, children, and even his painful piles. It is a nuanced and masterful performance worthy of a Beckett play, with canny direction from the late Tony Milner.
Grudges are aired: from class differences to the disparity in fame and recognition the crew received on their return, which involves a reckoning with Shackleton. McNish was never given the Polar medal, he tells us repeatedly, and although he was key to their survival, modifying a small boat that allowed Shackleton to fetch help, he was written out of the heroic narrative spun on the crew’s return.
While there are moving moments in Gail Louw’s script, it feels dense with names, unseen characters, factual details and scores to settle but with not enough revelation or dramatic focus to the narrative. We must work with McNish to be carried along in this gruelling voyage to his past and sometimes, it feels like hard work.
• At Jermyn Street theatre, London, until 17 August. Then touring until 18 December.