THIS is not a little voice – this is a great BIG VOICE. So powerful that when Jess Robinson belts out her Shirley Bassey, her Tina Turner and her Streisand, there isn’t a dry eye in the house.

Simon Thorp’s gloriously seedy impresario Ray Say, is absolutely right, a show like that would go right to the top. Except that the whole play is about how this young woman’s singing talent has developed from anguish and a desire to hide away, not to stand in front of thousands.

Beverley Callard as Little Voice’s bold and brassy mum, Mari is a Shakespearian heroine, lithe and witty with perfect body language and magnificent ownership of the great writing in this play. She flows through it like silk.

This is such a generous play. It has everything in it, comedy, tragedy, misunderstanding and some great, great songs. Ingeniously, it all runs side by side. It is sad and funny all at once and brilliant entertainment.

Little Voice is a troubled young woman who, grieving for her dead father, a sensitive man, just wants to stay in her room and sing along to the records he left her. Her mother, who thought her father was actually a bit of a miserable bugger, likes to live it large and wants to find a man for ditto. She nearly finds one but he is only interested in making a lot of money out of promoting Little Voice. But all Little Voice wants to do is stay in her room.

As, her mother Mari says to her, in frustration: “If you are angoraphobic – you can get out of here!”

Audiences are advised to get in their seats 10 minutes before the show starts. The glittering Duggie Brown (once a member of the television show The Comedians and wearing this role as comfortably as a pair of old tartan slippers) begins his night front of house chatting at the bar. He doesn’t look like the usual member of a Cambridge audience, in his gold sequin jacket, his red satin frilly shirt and his auburn toupee.

Then he walks up onto the stage introduces himself as Mr Boo and starts talking about a raffle and the whippet charity the club is raising money for tonight. Then, ladies and gentlemen, he introduces the first act – a dance duo called something like “Sugar and Lump”.

The audience was still coming into the auditorium and some of them hadn’t quite worked out that the show had started but for those of us who had, it was a joy from then on.

The smile never left my face, even when tears rolled down it. It’s ecstasy. It’s not just entertainment. It’s a fix.