The morning after seeing The Rat Pack this week, I turned on Radio 2 to find Aled Jones playing Frank Sinatra and marvelling that it was now ten years since this wonderful entertainer died. "I can't believe he's not still with us." Well, Aled, you would certainly have thought he was had you joined me the night before in the packed house at Milton Keynes Theatre where Stephen Triffitt was supplying his astonishing impersonation of Ol' Blue Eyes.

With eyes closed you'd swear you were hearing the entertainer's familiar lilting voice belting out such classic numbers as The Lady is a Tramp, My Kinda Town (Chicago Is), (I've Got You) Under My Skin and New York, New York. Open them and the illusion remains, for Triffitt bears a remarkable similarity to the young Frank, as you can see from the picture above.

Furthermore - and this is perhaps his chief achievement in this marvellous show - he talks and behaves like the legendary star. This is seen in the jolly, joshing relationship Sinatra is shown enjoying with his friends Dean Martin and Sammy Davis Junior. These two are very ably portrayed in the production, which recreates the sort of show the trio supplied to the well-heeled punters of Las Vegas, at the height of their fame. Seemingly chaotic, these cabaret performances would surely have been carefully planned, with every throwaway line rehearsed in detail. The result, as with Morecambe and Wise, was total hilarity, well-caught here with a brilliant Nigel Casey as everyone's favourite drunk Dino - his stumble down the stairs is a marvel - and David Hayes revealing the talent for self-deprecation, as well as the boundless confidence, of "the performers' performer" Sammy Davis.

Both proved almost a match for Triffitt vocally, in songs delivered with a 15-piece orchestra conducted by Dominic Barlow and sometimes with the involvement of Sophie McEwan, Lisa Donmall and Lucy Holloway, as the high-kicking, high-note-hitting Burelli Sisters. Hayes brought tears to everyone's eyes with his interpretation of Jerry Jeff Walker's Mr Bojangles, and Casey excelled on That's Amore and An Evening in Roma. I would like to have heard him sing Gentle on my Mind, but you can't have everything. Together these artists had enough classics to fill a show lasting the four days that 'Sinatra' joked this one would.

In fact, it lasted a little over two hours and ended - how else? - with the tear-jerking My Way.

The Rat Pack Live from Las Vegas continues until tomorrow. Box office: 0870 060 6652 (www.miltonkeynestheatre.com).