She may be older than John Prescott and camper than Liberace but Dame Shirley Bassey’s sold-out homecoming show in Cardiff on Tuesday was greeted with all the fervour of a papal visit. Materialising onstage in a bejewelled Julien Macdonald gown of eye-watering canary yellow, the former local girl made good was on tremendous form, all gym-toned arms and expensive hair. Right across South Wales, gay bars and sheltered housing for the elderly stood eerily absent.

Dame Shirley is not a natural garrulous, over-eager crowd-pleaser, in the Robbie Williams or Liza Minnelli vein. Between songs her smile was glazed and her banter stilted. Even when she paid obligatory homage to her home town of Cardiff, complete with exaggerated Welsh vowels, she sounded as magnificently insincere as a squeamish politician kissing a sickly baby.

But when her 20-piece orchestra swelled behind her, Bassey seized control of the room with an all-conquering voice that remains arrestingly potent, even at 69. Booming and operatic, she is more Tom Jones than Charlotte Church, more Freddie Mercury than Diana Ross. But in Jeremy Clarkson terms, her tonsils are Ferrari thoroughbreds, shifting up through the gears from zero to 100 miles an hour with impressive power and control. Beyond all the camp trimmings, this effortless emotional clout explains why she remains an arena-filling diva.

The 90-minute set was heavy on Broadway showtunes and jazzy standards. Old favourites including Hey Big Spender and The Lady is a Tramp were delivered with a raunchy swagger that bordered on self-parody. But Bassey sounded more convincing on epic, heartbroken ballads such as I Just Have to Breathe and Here’s to Life. Nobody does lip-trembling defiance and tragic melodrama better than Dame Shirley.

The most baffling omissions were Bassey’s more recent chart hits, notably her 1997 Propellerheads collaboration, History Repeating. Indeed, considering that Diamonds are Forever was recently sampled by superstar rapper Kanye West, her choice of songs was disappointingly safe. Besides a brace of Beatles covers and a medley of James Bond themes, most of Tuesday’s set could have been lifted directly from a Royal Variety Show from 40 years ago.

At the climax of the show, Bassey was ritually bombarded with cakes, champagne and gifts by adoring fans. And then, with one last wave of her weightlifter’s arms, she floated backstage to be whisked away to her own private Narnia, possibly in a chariot made entirely of diamonds.