British sprinter Zharnel Hughes has said he is "heartbroken" after being disqualified from the men's 100m final at the Tokyo Olympics, as Italy's Lamont Marcell Jacobs won a shock gold.

Jacobs is the first man to win the title other than sprinting great Usain Bolt since 2004 as he crossed the finish line in 9.8 seconds.

There was drama before the race after a blatant false start from Hughes meant he was unable to compete and had to watch the final from the sidelines.

Image: Lamont Marcell Jacobs celebrates after winning gold in 100m men's final
Image: Jacobs (second right) crosses the finish line

Hughes was set to be the first Briton to race in the men's Olympic 100m final since Dwain Chambers and Darren Campbell at the Sydney Games in 2000.

Speaking after the event, he blamed the false start on cramp in his left calf as he took his position in the starting blocks.

"With the cramp, I moved," he told the BBC.

"I feel that if I was in the final I would have walked away with a medal, no doubt about it.

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"It was out of my control. It hurts a lot."

Hughes later said that his cramp was "so severe" he "just couldn't stay" in his blocks despite having been fine in the warm-up.

The 26-year-old, who was born and raised in the British overseas territory Anguilla, said he was trying to "think of something positive" and refocus for the men's 4x100m event.

"I'm really heartbroken right now," Hughes added.

"Wrong time and wrong place."

Image: Hughes blamed his false start on cramp. Pic: AP
Image: Hughes is led away by an official after being disqualified. Pic: AP

The scenes were reminiscent of Linford Christie's disqualification before the 1996 Olympic 100m final in Atlanta following his two false starts.

The rules changed in 2010 so now one false start means instant disqualification.

Italian Jacobs, who only switched to sprinting from long jump in 2018, won the race in 9.8 seconds, edging out America's Fred Kerley by 0.04secs.

Image: Jacobs won the race in 9.8 seconds
Image: Lamont Marcell Jacobs celebrates after winning Olympic gold

Canada's Andre De Grasse collected a second successive bronze in the event, having also finished third at Rio 2016.

Jacobs - who was born in Texas but moved to Europe with his Italian mother as a child - said after the race that winning the Olympic 100m title had been his dream since he was a youngster.

"I need a week or so to understand what has happened," he said.

"I've won an Olympic gold after Usain Bolt, it's unbelievable.

"Tonight, staring at the ceiling perhaps I will realise."

American Trayvon Bromell had been favourite to win the 100m title before the Games after running the world's fastest time this year at 9.77, but he failed to qualify for the final.