Helen Mirren was stylish throughout. The script's blowzy drink- soaked rock star could have been a cliche, but Mirren's portrayal was deft: louche but not yet raddled, past-it but not spiritually broken, clinging on amid the accoutrements of past success and present sufficiency

"She's a fully-sexed mature woman who is neither madonna nor whore... the temptress who becomes executioner," said the art lecturer, purportedly talking about a 17th century depiction of the biblical character Judith who cut the head from the mighty Holofernes, head of the army of Nebuchadnezzar. But, of course, we all knew she was talking about Helen Mirren who, having declined to undertake a Prime Suspect III, this week instead became the Painted Lady (ITV) in a four-hour Granada extravaganza of death, decadence and detection.

It was a splendid canvas for her steely sexuality. The story wove its way along the interstices of four worlds - fading Anglo-Irish gentility, low-life gangsterism, glossy international art-dealing and the smoky New York jazz scene - and Mirren was able to play different characters in each of them. It began, on Sunday, in a crumbling mansion outside Dublin where an amiable old aristocrat, Sir Charles Stafford, had given over the lodge to an ex-Sixties rock star, Maggie Sheridan, now recovering from heroin addict and recording no-hope blues with her young lover in a living room littered with Hendrix on vinyl, black leather jackets and framed cuttings of yellowing triumphs. But Stafford was soon killed by burglars out to steal his collection of old masters and Maggie, played by Mirren, was swiftly drawn into a plot of Byzantine complexity.

At its heart was a conceit. The paintings had been sent to Stafford, one at a time over four decades, like postcards from an old acquaintance. And each - The Agony In The Garden, The Martyrdom of St Cecilia, The Drunken Silenus, The Penitent Magdelene - echoed events in the old man's life which the plot slowly unravelled. There was much that was inherently implausible - that the villain would own appropriate paintings for each event, that the police would drop out of the picture so quickly after the murder, that an old rocker could fool top dealers into thinking she was a fine art expert, and so forth. But the thriller is the latter-day equivalent of the melodrama, so the coincidences came in appropriate measure, along with moments which made the adrenalin pump and the occasional helping of ham in the dialogue.

"Maybe it's not too late to get to know him," said lamenting son, Sebastian, resolving to solve the riddle of his father's murder. "I know where you live," said one gangster boss to a hapless Irish cop. "We're busy in here," snarled Ms Mirren to a man who stumbled into the gents where she was holding a broken bottle to her ex-boyfriend's neck. It was a tribute to the sheer quality of the performances that such lines did not break our suspension of disbelief.

Helen Mirren was stylish throughout. The script's blowzy drink-soaked rock star could have been a cliche, but Mirren's portrayal was deft: louche but not yet raddled, past-it but not spiritually broken, clinging on amid the accoutrements of past success and present sufficiency. Her more domestic moments with her sister subtly blended a mordant manipulativeness with a deeper affection and concern. And her performance as the art-dealing Polish countess had delightful touches of parody. She was well-supported by a cool yet caring Lesley Manville as her art dealer sister and by the sultry taciturnity of Franco Nero as the arch-villain. And Iain Glen gave good Brideshead as the fey bisexual Sebastian, even if the gay bondage scene seemed gratuitous until the crossbow appeared and the significance of Sebastian's saintly name became unpleasantly clear.

The concluding part, last night, was less satisfactory. It seemed broken- backed after the death of Sebastian. The denouement in New York lacked the menace of the earlier Irish scenes and took on a more conventional cops-and-robbers feel. Nevertheless it adroitly developed the earlier repeated scenes from Sir Charles Stafford's family movie, turning black and white into colour for the key scene which revealed the ambiguity of the relationship between Stafford and the villain in the looting of treasures as the Nazis retreated by war-time Italy. Perhaps the painting allegory in the final scenes was a little too exactly worked out, but this was a world where justice was poetic - and we'd all be the poorer without that.