Joy instantly turned to despair at Royal Ascot on Saturday when Thomas Chippendale lost his life after winning the Hardwicke Stakes for trainer Lady Cecil and jockey Johnny Murtagh.

The four-year-old colt collapsed and died of a suspected heart attack after passing the line in a dramatic, and deeply sombre, renewal of the Group Two over a mile and a half.

Murtagh said: “He ran his heart out and was pulled up at the line. He lost his balance and I don’t know what happened to him.

“It’s heartbreaking for everyone involved – it should have been a great win. It’s just devastating the way it’s finished.”

The sense of sadness was felt even more sharply by the fact Sir Henry Cecil, Thomas Chippendale’s former trainer and wife of Lady Cecil, died recently.

Of Thomas Chippendale, Lady Cecil said: “I’m heartbroken, it was devastating, but at least it was quick and he wouldn’t have felt anything.

“I didn’t know what had happened until I came back. I thought everything was all right but it seemed all quiet and I had no idea why. The horse had been working so well.”

Asked about her decision to come racing this week following her husband’s death, Lady Cecil said: “I’ve had to keep going for Team Cecil and for Henry.”

Lady Cecil said connections of Thomas Chippendale had gone from “a real high to a real low”.

She said: “I have to say that leading up to the race he was in such good form. He was enjoying himself.

“We had never been happier with him beforehand. We were thrilled when he won and now we feel so bad.

“The horse and jockey seemed fine so I wondered what had happened. We’ve gone from one emotion to the other, from a real high to a real low.

“I feel so sorry for poor Sir Robert (Ogden, owner). He’d been looking forward so much to this day and I just don’t know what to say.”

In what was a most dramatic encounter, Ektihaam (9 to 4 favourite) also slipped up on the bend and gave Paul Hanagan a nasty fall.

The horse returned to the paddock unscathed, but Hanagan was sent to hospital for X-rays.

Hanagan set off to make all of the running – tactics he had employed last time out when beating Thomas Chippendale by six lengths.

Universal took up the running following Ektihaam’s departure and had a good break on the field, but the challengers were stacking up two furlongs out.

Murtagh kicked for home well over a furlong out, but Frankie Dettori, still searching a first win of the week, got a great tune out of Dandino.

He could not sustain his challenge, however, and went down by a length to the 8 to 1 scorer, with Universal another two and a half lengths back in third.

Luca Cumani's Mount Athos and the supplemented Sir John Hawkwood never threatened to get involved.

Lethal Force ran out a hugely impressive winner of the Diamond Jubilee Stakes for trainer Clive Cox and jockey Adam Kirby.

The four-year-old grey made just about every yard of the running and burst clear two furlongs out.

The 4 to 1 favourite Society Rock made up relentless ground under Kieren Fallon and at one stage looked likely to reel in the leader.

However, Kirby kept Lethal Force up to his work and the 11 to 1 chance crossed the line two lengths clear.

Lethal Force had been narrowly behind Society Rock last time out at York but was 5lb worse off here.

Krypton Factor (25 to 1) finished well for third, with Gordon Lord Byron and Sea Siren close up behind.

Jamie Spencer partnered York Glory to a clear-cut victory in the Wokingham Stakes.

Held up right at the back of the pack, Kevin Ryan’s grey got a perfect split on the inside of Shropshire.

The 14 to 1 chance powered home to give trainer Kevin Ryan a second winner of the week after Lightning Cloud’s success on Friday in the Buckingham Palace Stakes.

Kieren Fallon kicked early on the well-backed Gabriel’s Lad but he looked a sitting duck a furlong out.

Shropshire had made eyecatching progress to hit the front but Spencer always looked to have his measure and galloped clear to win by a length and three-quarters.

Dinkum Diamond was third, with Khubala fourth and Glass Office fifth.

Paul Cole's Berkshire ran out a convincing winner of the Chesham Stakes . Sent off at 16 to 1 after finishing third on his debut at Newbury, the Jim Crowley-ridden winner came from last to first within a matter of strides.

Drawn 21 of 21, the son of Mount Nelson bounded two and a half lengths clear of 11 to 4 favourite Bunker, with Godolphin’s Ihtimal third.

Cole used to be a man renowned for his training of two-year-olds and was winning the race for a fourth time.

Crowley said: “I was lucky enough to get the ride at Newbury and he was in front all the way that day and did it the wrong way.