Theatre: Any resemblance is entirely coincidental

Battle Royal Lyttelton, London The Old Curiosity Shop Southwark Playhouse, London

What a difference 200 years don't make. Nick Stafford's Battle Royal begins in 1795 with a Prince of Wales who's pressurised into marriage to produce an heir but who's already in love with - indeed, clandestinely married to - a Catholic widow. It ends with his lamenting that "I've waited all my life to be King", only to find that vociferous popular opinion, violently manipulated by republican radicals, is on the side of his misused but feisty wife. In between, she finds herself imprisoned and friendless within the royal household, while the newspapers peddle gossip about the royal relationship. When she escapes overseas on an annual allowance, the prime minister offers divorce counselling to the heir to the throne in the form of politicised, public relations advice. Then there's obsessive and prurient interest, from the populace to the peers, in the details of the would-be Queen's adulterous affair with a foreign commoner.

But unlike Alan Bennett's incisive, further-reaching account of this Prince of Wales's father, Stafford's The Mindlessness of the Future George IV only works on the level of "what-if?" contemporary extrapolations. There are definitely more than three people in evidence in this royal marriage. The play closes with the wronged Princess Caroline of Brunswick dying an early death, having sacrificed happiness with her Italian lover only to be barred from taking up her rightful place at her husband's coronation. It's a moving end. But the only response afforded by this overlong chronicle is rueful - and familiar - indignation. Or, as the American behind me put it: "Aw. I wanted her to be Queen."

But, thanks to the cast's handling of Stafford's sparky script, Battle Royal is often an enjoyable romp. Simon Russell Beale's Prince George is petulant, profligate and impossibly self-centred, always standing, one foot on tiptoe, as if he's on the verge of cantering off stage like a wilful pony. His comic timing is unforced, and he raises as many laughs with his array of wigs. One involves a quiff like a miniature bale of hay; another, with sideburns, makes him look like a chubby Noddy Holder. As Caroline, Zoe Wanamaker growls her way through the play with Germanic- accented glee, and she employs her full range of girlish eccentricities. But some of her more hysterical, impetuous reactions to her treatment arrive, under Howard Davies's direction, with self-conscious alacrity.

To condense more than 500 pages of Dickensian description into a two- and-a-half-hour fringe adaptation is no mean feat. Stephen Sharkey's version of The Old Curiosity Shop takes several liberties with Little Nell and her story. But it never strays from solid, old-fashioned, family-oriented storytelling. Erica Whyman's direction is occasionally ponderous, but she imaginatively utilises the small space to bring - from all angles - Dickens's characters to larger-than-life existence.

Episodes of comic exuberance, involving creations such as Roz McCutcheon's gaudy Mrs Jarley and a black-frocked Malcolm Ridley as the "dragon" Sally Brass, only emphasise Sharkey's jolting compression of the convoluted plot. Such that the pitiful trials of Little Nell (Diveen Henry) and her grandfather (Yemi Ajibade) have faded from focus long before the tragic end, which Whyman dwells on with melancholic grace. But the show belongs to Jonathan Coyne's Quilp, a cross between a malevolent Bob Hoskins and a slug. His lurching performance is a villainous delight - though any children unfortunate enough to be seated within his eyebrow-raising, sneering range of vision may well have seen it differently.

`Battle Royal': Lyttelton, SE1 (0171 452 3000) booking to 29 January. `The Old Curiosity Shop': Southwark Playhouse, SE1 (0171 652 2224) to 15 January.