WHEN the star of your show falls ill before opening night, it really is a Nightmare on Lime Street (or Roe Street, if you’re pedantic about these things).

American producer David Gest may be laid up with gastroenteritis but the Royal Court’s Christmas show must go on.

And go on it does – albeit in surreal fashion, with stand-in Anthony Watson playing David Gest playing Frankenstein’s Monster, who was David Gest before he was turned into the green faced, flat-headed creature after a stroll along Bold Street.

Watson is a endearing version of the monster who can’t bring himself to be bad but hearing him spout Gest’s catchphrases (“Holy Foccacia!”) is undeniably odd.

Before all that, we’re taken to Liverpool in the 1800s and the secret base under Lime Street station of Dr Frankenstein (Mark Moraghan), curator of antiquities at Liverpool Museum.

His wicked ways are halted when a potion mixed by hapless assistant Egor (Lenny Wood) puts them both to sleep for 150 years.

Fired from his job, he wakes up wanting to destroy the city with super-lamba-daleks – and wannabe ghosthunter Tommy (Michael Starke), daughter (and reluctant sidekick) Julie (Jamie Hampson) and crucifix-flogging nun Sister Sledge (Lynn Francis) all fall into his grasp.

It’s all very silly but great fun, with some nice Thriller-inspired choreography and a talented, energetic cast who are clearly having a good time.

The action is played out against sumptuous – and detailed – sets of Lime Street station, Frankenstein’s lair and a moonlit Liver Buildings rooftop.

Michael Starke makes a hilarious entrance to Ghostbusters theme tune and is a hoot, all comedy facial expressions and knowing looks to the audience. He and real-life daughter Jamie Hampson make for a winning partnership.

The local references are present and correct. The Grafton, Cilla Black, Derek Acorah, Pete Price and even X Factor’s Christopher Maloney get a mention – the latter suggested when Dr Frankenstein is looking for a “despicably heinous” human being.

All the ingredients are there for a fabulous festive treat – dancing, songs, lame panto-esque jokes (“Was he a Beatles fan?” “Yes, he say hello I say goodbye”) – yet at times the show feels strangely flat.

It’s not helped by a plot which spends too long at Lime Street in the first act and takes an age to get going.

It’s far from a nightmare, but really does miss its star attraction.