There’s something very enticing about watching theatre in the vaults at Waterloo: the dingy chambers filled with passionate pieces of up-and-coming theatre, the makeshift, bottom-numbing wooden benches and the all-encompassing boom of trains passing overhead. Here in this underground performing arts haven, Vault Festival is back for the fourth year in a row, and opening the festival is Over The Limit Theatre with their new show, Gentle Tim. Following the true story of Timothy Treadwell – bear enthusiast, documentary filmmaker and subject of Werner Herzog’s 2005 documentary Grizzly Man – Joseph Cullen’s writing revives the character, honing in on aspects of his story and dissecting these on stage.

Timothy’s (Joseph Cullen) silent companions on stage – Laura Meaton, Marah Wilson, Jason Kajdi and William Uden – are all in the role of bears and loyally support Cullen in what would otherwise be a one-man show. Tussling with one another and eerily observing Cullen from the shadows, the decision for the bears to be played by actors is an aesthetic visualisation of Timothy’s desire to humanise animals. Brought to life through physical theatre, the bears are simple in form but captivating, and Meaton’s choreography, which sees the bears sniffing, rolling and raising themselves gawkily onto their hind legs, is spot on. In contrast, Timmy the fox is represented in Gentle Tim by a soft toy as opposed to an actor, perhaps in order to reflect Timothy’s desire for his ‘friend’, the fox, to be domesticated.

With Gentle Tim taking place in the round, Timothy’s video camera – the device fundamental to recording his summers in Alaska – nestles into place beside us like a member of the audience. As in Grizzly Man, Timmy the fox and the video camera become Timothy’s non-judgemental friends – the silent listeners who, from a theatrical point of view, give him reason to speak his thoughts out loud, and in an alternative form to monologue. Only when Timothy is not talking to Timmy the fox, or the camera, do we get a look at his darker, internalised thoughts. These moments are envisioned creditably here through Gregory Jordan’s lighting design, which places Timothy under a spotlight engulfed in a pool of red during his moments of self-doubt and reflection on his drug-fuelled past.

Cullen captures the erratic and socially awkward nature of Timothy Treadwell. With his bleach blonde hair, backwards cap and mountaineer’s attire, Cullen looks every bit his character. Rejuvenating the humour we laughed at with affection in Grizzly Man, he authentically brings to life the man who believed he had “the mind of a bear”. One slight disappointment is that Gentle Tim is flat in tone and plot progression. In the snippets of his life that we see, no new views on Timothy Treadwell are brought to the table, and we don’t learn anything about him that we didn’t already know from watching Grizzly Man. Overall, however, it’s an excellent up-close and personal character exploration that trails off before Timothy meets his partner (Amie Huguenard) or his grizzly end.

Gentle Tim is playing as part of the Vault Festival until 31 January. For more information and tickets, see the Vault Festival website.