WEDNESDAY sees the start of the four best days in the Yorkshire racing calendar – some would even say they are the best days in any calendar – with the Ebor Festival at York set to burst into life.

One horse that will not be there is the Roger Charlton-trained Time Test, one of the leading challengers to Postponed in the Juddmonte International Stakes.

Time Test, owned by race sponsor Khalid Abdullah, won the York Stakes over the same course and distance last month, but Charlton said that all had not gone smoothly since.

"He worked this morning with Countermeasure, his normal lead horse," the trainer said on Wednesday afternoon. "Every time he's worked this year he's moved up on the bridle and then quickens four or five lengths clear. Today he just worked a little bit flat."

Charlton added: "He moved up as if he's going to go winging past him, but didn't. His regular rider said he thought he worked a bit flat and it wasn't him. The Juddmonte next week is naturally a proper Group 1 race with some very good horses in it, but there's no point running in a race like that if your gut feeling tells you the horse isn't 100 per cent, so we decided to scratch."

Asked about future plans for Time Test, Charlton said: "We'll go through the normal tests, give him a break and I guess he will tell us where he's going to run, but it's too early to say."

Charlton had more positive updates on Fair Eva, who is set to take part in the Lowther Stakes, Imperial Aviator, who takes his chance in the Great Voltigeur, and Quest For More in the Lonsdale Cup, who all remain on track for a trip to the Knavesmire.

Charlton said: "George Baker rode Fair Eva this morning on our summer gallops and she worked with a lead horse over five and a half, six furlongs and he was impressed. She looks very well.

Like all things, we need to get through the next few days, but she’s in good shape and we’re looking forward to seeing her run at York."

Clearly smitten with the ante-post Qipco 1,000 Guineas favourite, Charlton added: "She’s different in that she’s better than horses I’ve dealt with in the past. Sadly, we don’t seem to get lots of really amazing two-year-olds, but she’s certainly pretty special.

"She’s got a great temperament and she’s a great eater. A lot of horses that move very well don’t actually quicken, but she gets down low and quickens. We saw that at Haydock and Ascot and I think if she’d been more vigorously ridden at Ascot she would have broken the track record."

Jump racing is set to be a little poorer this season with the news that Paul Carberry has been forced to retire from the saddle after a meeting with an orthopaedic specialist earlier in the week.

Carberry, 42, was one of the most talented riders of his generation, but has not ridden competitively since last September, when he fractured his left femur in a fall at Listowel.

He then had to undergo further surgery when he cracked the steel reinforcements in his leg in a fall at home in January.

On Tuesday, Carberry met well-known orthopaedic surgeon Dr Paddy Kenny at Connolly Memorial Hospital, in Blanchardstown, who advised him not to pursue a return to the saddle.

"It didn't go great," Carberry revealed. "Dr Kenny said that the leg is still too weak and that I'd be better off not coming back – he couldn't pass me fit to ride. I suppose I knew the last month that the leg wasn't getting stronger, but it is still a blow. I was half hoping that I might get back. It's a day that had to come at some stage, but it's difficult to take. I am gutted."

Carberry rode a host of big-race winners during his career, including his father Tommy's Bobbyjo in the 1999 Grand National at Aintree.

Reflecting on his career, he said: "The National is the highlight. It was a dream come true. To win the National was always my dream, but then to win it for my father was unreal altogether.

"He had been the last to ride an Irish winner of it before me (on L'Escargot in 1975), so it was a big family day. I've had a chat with dad and this is sad for him too, because I've never known anything else, but he said to listen to the doctors, because they know best."

Carberry developed an enduring relationship with his County Meath neighbour Noel Meade. Their association would prove one of the most successful Irish jumps combinations in recent times, notwithstanding Harchibald's contentious 2005 Champion Hurdle defeat to his nemesis Hardy Eustace in what was an utterly mesmerising spectacle.

Carberry said: "I had a great time and rode a lot of good winners in big races, especially for Noel. Harchibald was the best horse I rode for him and winning the title a couple of times was special as well. Noel was easy enough to work for and a great friend."

A 14-time winner at the Cheltenham Festival, Carberry was two-time champion jockey in Ireland, in 2002 and 2003, and he rode nearly 1,600 winners since first tasting success on the Jim Bolger-trained Petronelli at Leopardstown in 1990.