What makes a good comedian? It’s impossible to tell, I’ve seen so many that I have loved one week and felt drained by the next. There are few that I’d recommend, I don’t like the pressure of trying to foresee whether or not they’ll have a good night or whether they tickle my fancy alone. I’ve stumbled across a comedian gauge though, and that comes in the form of my Nana. A woman I have known for 20-odd years, who is small and yet utterly formidable. In that time, I can count the amount of times I have seen her smile on one hand and have seen her laugh twice. Both times occurred at the Edinburgh Festival. Once, uncontrollably, at The Play That Goes Wrong and one at Vikki Stone. The latter seemed inconceivable at the time: there were sexual references, some at the expense of Professor Brian Cox. Who, in a completely unpredictable turn of events, happened to be my Nan’s one and only claim to fame, having made him a toad in the hole at the tender age of 13 as one of my uncle’s school friends. She has anecdotally boasted about it at every opportunity since he first popped onto our screens. Now there he was featured in one of Stone’s, note-perfect, hilariously written songs as a piece of meat; an object of desire. Still my Nan’s shoulders shook with laughter.

In Instrumental Stone begins by promising us that she will underscore the show by playing 20 instruments. Some of which she plays impeccably, with all the training and talent that she can muster, some not so well but which are either insignificant or gag-enhancing. Turns out, Instrumental isn’t solely reliant on how many instruments it involves (however much awe that conjures) but about what is instrumental in making a life. In Stone’s case it’s obviously heavily involved in music, but the instruments themselves are secondary to that; how she acquired, the people that gave them to her, or how she procured them by other means is what is important. Instrumental is about her dad: from how he obtained Vikki’s first piano, to how he amusingly embarrassed her, supported her and disappointed her over the years. How he was a doppelganger to the Chuckle Brothers (both) and how he was an alcoholic.

That last bit isn’t exactly a barrel of laughs, I know, but somehow Stone derives humour from it. There’s an instinctive warmness you feel when watching something completely honest. Similarly, watching someone reminisce about areas of a normal upbringing that we can all relate to, Butlins-style holidays, embarrassing fancy dress and old, unrecognisable photographs, is instantaneously funny. She pumps up the action with audience participation, songs and keytar that tips us all over the edge, not to mention the sheer skill involved in playing 20 instruments, recording them and looping them while delivering an hour’s worth of material. It had all the natural humour that Les Dawson pioneered in his piano-based scats, but Stone doesn’t even have to play it badly to be funny.

Vikki Stone manages to do what is, to me, the most admirable thing a comic can do: make me laugh my socks off and make me cry like a baby without any awareness that I’m doing it. By making us laugh she grabbed our emotions and brought them right to the surface, putting them in prime position for a pummelling, and making us sob at her honesty at a drop of hat.

There were times when I thought her script was a smidge over-prepared, lacking in naturalness, in favour of concentrating on what instrument was coming next or not tripping over wires. Stone’s main message is, that things may not always go as planned but she will always have a bloody good bash at it. In my eyes, there’s no use trying when you’ve already succeeded as triumphantly as that.

Vikki Stone: Instrumental is currently on tour. For tickets and more information, see Vikki Stone’s website.