In the nine years that I've been reviewing for the British Theatre Guide, the Classic Thriller Season at the Theatre Royal has been a constant, consistent element of the summer theatrical calendar.
Apart from outdoor productions, there are usually few rival attractions because most theatres are dark. The Classic Thriller Season offers entertainment that's not too taxing on what can be a warm evening and it's far better than most of the sub-standard fare on television.
The late Theatre Royal managing director James Ashworth described the season as "like a comfortable pair of old slippers; old friends returning to perform a good yarn in a period setting".
Occasionally the acting company have taken to the stage with their tongues firmly in their cheeks: I vividly remember Colin McIntyre's 2004 spoof of Bram Stoker's Dracula whose flying bat confirmed that the production was destined not to compete with anything from the Hammer House of Horror.
In that show, Classic Thriller Season stalwart Nicholas Briggs played the lead. This year he was Dr Sam Kennedy in Sweet Revenge and Inspector Pratt in Peter Gordon's hilarious Death by Fatal Murder.
But he's also the director and sound designer for Strangers on a Train. It was during the interval that my wife Sue and I both agreed: this is the finest play we've ever seen in the Classic Thriller Season.
Craig Warner's adaptation of Patricia Highsmith's novel is a commendable starting point: there's a clever plot which has two main characters going through individual transformations as they make life-changing decisions; and there's an inherent tension which builds grippingly towards the interval and at the end.
Excellent acting - there's not a weak link in the cast - combined with assured direction and Geoff Gilder's inventive, multi-layered set make for a startlingly good production.
Strangers on a Train, set in America in the 1950s, tells how Charles Bruno and Guy Haines meet and confess their troubles to each other. Bruno comes up with the idea of killing Haines' wife who's taking him through a painful, costly divorce in return for Haines' killing Bruno's domineering father. It would be a perfect pair of murders, says Bruno.
Chris Sheridan, who's in his first Classic Thriller Season, gives a stunning performance as obsessional Bruno. He initially seems to be merely an opportunist but later talks about "the wonder of death". He's on the verge of insanity when he writes to Haines insisting that the stranger kills Haines' father and Sheridan is so convincing when he's suffering from alcoholism that I thought the curtain would come down and someone would call "is there a doctor in the house?"
I wondered whether Sam Clemens as Haines was projecting enough at the beginning as he sounded very quiet. But it was part of his character's mild, indifferent attitude to life. But when faced with the moral complexities of his disheartening dilemma he becomes angry, insular and irrational. It's a thrilling portrayal of a man who fails to deal with an unthinkable situation and how it affects his whole life.
There's terrific support from Karen Henson as Bruno's mother Elsie; Jo Castleton as Haines' second wife Anne; Al Naed as Haines' colleague Frank Myers; Jeremy Lloyd Thomas as Haines' old friend Robert Treacher; and John Hester as private detective Arthur Gerard.
Briggs keeps the action taut right until the unexpected ending which appears to wrap everything up neatly but leaves unanswered questions about whether the survivors will cope with their new situation.
Some of the productions in previous Classic Thriller Seasons haven't always been on the right lines - but Strangers on a Train is first class and should prove to be a platform for future success.
The Classic Thriller Season concludes with Brian Clemens' "Murderous Liaisons" from 30th August until 3rd September