Eric and Little Ern, St James Theatre

The audience for this show could probably be divided into to two camps: those who fondly remember watching Morecambe & Wise on ITV or the BBC, and those who weren't even born when Eric Morecambe died in 1984. The latter group may know the double act from repeats, of course (which remind us of how great they were and how many of their successors pale by comparison), but if they are new to Eric Morecambe and Ernie Wise, then Jonty Stephens and Ian Ashpitel's show is a good entry point.

It helps to explain why in their heyday M&W were the most successful pairing in comedy, why stars would queue to appear on their Christmas shows and why the 1977 edition was watched by a record 28 million people.

The story begins in 1999, where Ernie (Ashpitel) is on his deathbed in hospital. A white-coated doctor enters the room, and when he puts on his glasses to read Ernie's notes he's immediately transformed into Eric (Stephens), here to “fetch” his friend and erstwhile colleague over to the other side. But before that happens the two old pals, who met as teenagers on the variety circuit and formed a double act at Morecambe's mother's suggestion in 1941, reminisce and run through some of their old gags and routines.

The show is a neat conflation of original material – by Eddie Braben, Dick Hills and Sid Green – and a narrative structure devised by the performers and director Owen Lewis. Such an approach means we get to enjoy some old favourites – including the Grieg Piano Concerto, Hamlet's soliloquy, and the brown paper bag – while being given some insights into Eric and Ernie's working relationship. The joins are mostly as seamless as Ernie's famed “wig”, with the occasional clunk of a factoid lobbed in.

Ernie complains that Eric was (like so many comics) always “on”, which comes as no surprise, but the show also has some nuggets of new information – I never knew that Wise often didn't have his lines down pat for the TV show, for instance, or that Morecambe was unwilling to try to crack America despite Wise's keenness. We also get a touching glimpse of how Wise felt after losing his comedy partner of 40-odd years - “There was always a draught down one side” - and the affection the two men felt for each other.

Stephens and Ashpitel bear a remarkable resemblance to the comics and their recreation of the “front of curtain” routines Morecambe & Wise did at the start of their TV shows is a delight - they expertly capture the facial expressions, the vocal cadences and the stage business of the duo. But this goes beyond mere parody or even tribute, as the very real affection they have for their subjects is obvious. 

The show was conceived for the Edinburgh Fringe and expanded for its touring version, and now its Christmas run in London. While it could never quite match the original, it's still pretty damn good.

• Eric and Little Ern at St James Theatre, London SW1 until 11 January