Bernstein will miss the Middle Park Stakes at Newmarket today after a last-minute setback. A spokesman for trainer Aidan O'Brien explained last night: "We were not happy with his blood-count result this evening."

The juvenile looked set to be sent off favourite for the six-furlong Group One contest having appeared not to stay a mile in the National Stakes at the Curragh when sent off the 4 to 11 favourite.

Michael Kinane will switch to Bernstein's stablemate Brahms in what is now a six-runner event.

Primo Valentino, winner of his last four races, is sure to be strongly fancied having defeated Tuesday's Cheveley Park Stakes winner Seazun by half-a-length on his penultimate start. And last time the Peter Harris-trained colt made all the running to land the Group Two Mill Reef Stakes at Newbury.

Stable spokesman Simon Double said: "He's very well but there are one or two unknown quantities in the race like Fath for instance.

The Marcus Tregoning-trained Fath won his only start, a well-contested maiden at York, by two lengths from subsequent winner Tough Speed and has a big home reputation to live up to.

Invincible Spirit represents the in-form yard of John Dunlop and is sure to be well supported having defeated Khasayl and Femme Fatale - both of whom have subsequently landed Listed races - at Ripon last month.

John Gosden runs Warm Heart, beaten four lengths by O'Brien's Fasliyev in France last time and Nick Littmoden's progressive juvenile Trinculo completes the line-up.