Alexander Walker, one of the UK's best-known, longest-lasting and most highly-paid and influential film critics, died suddenly yesterday at the London Clinic. He was 73 and had been undergoing tests for cancer.

Walker, born in Portadown, Northern Ireland and educated at Queens University, Belfast, was critic of the London Evening Standard for some 43 years. He moved to the Standard from the Birmingham Post in 1960 after a personal letter of recommendation to the editor from Kenneth More, who had been delighted by one of his reviews.

As a controversial critic, who could whack a film-maker for a bad movie harder than most, he did not always delight. He was, in fact, cursed as much as praised. His campaigns against some of the policies of BAFTA, the BFI and the Film Council became almost legendary. Whatever you thought of his opinions, he was a first-class writer and his reviews remained as fresh and challenging when he became a veteran at the game as when he first started.

Apart from reviewing, he took a great and very knowledgeable interest in the industry both in the UK and in Hollywood and wrote 20 books about it and its stars. His biographies were invariably well researched and his Hollywood, England was one of the best about the post-war industry. He was also one of the few critics whom Stanley Kubrick allowed near him and wrote an appreciation of his films still read today by aspiring directors.

Walker, always immaculately turned out and usually extremely polite and friendly, nevertheless had a temper on him that sometimes almost brought the heavens down. He was not a man to cross. But he could also be a very good and helpful friend, even if you smoked, which to him was a cardinal sin.

When you rang him and got his answering machine, his message ended: "And remember, smoking is the slow way to suicide".

He lived alone in a flat at Maida Vale and his main relaxation from films was skiing. Otherwise, he lived almost entirely through his work. He once said that the fact that he was an insomniac enabled him to research and write his books. One of the attributes least known about him was his sense of humour. He was an excellent dinner companion, regaling those at many a table with a great many indiscreet and wonderfully told stories.