British swimmer Adam Peaty has won gold in the Rio Olympics, smashing his world record.

Peaty described the win as "so surreal", as his family and girlfriend wept with joy by the poolside.

He set a new world record of 57.13 seconds in the 100m breaststroke, beating an all-time best he had set himself just a day earlier.

Image: Who is Olympic gold-winner Adam Peaty? Image: At just 21, he holds three world records Image: Beating his childhood idol Cameron van der Burgh at the 2014 Glasgow Commonwealth Games put Peaty in the spotlight Image: Since winning gold at the 2014 Commonwealth Games, he hasn't stopped winning Image: The 21-year-old won gold in the European 50m breaststroke Image: He also set a world record in the 2015 World Swimming Championships in Kazan, Russia Image: Peaty beat his own world record in the heats in Rio with a time of 57.55 seconds in the 100m. He beat that again in the final with 57.13 Image: He grew up in Staffordshire and still lives at home where he has a dog called Monty Image: Former Olympic swimmer Melanie Marshall has been his coach since he was 12 Image: At 6.3ft (1.91m), Peaty is the fourth tallest member of Team GB Image: Peaty eats up to 8,000 calories a day to fuel his training Image: He's not always been keen to dive in. Peaty hated water and baths as a child Image: His mother says as a child, Peaty would scream and shout at the swimming pool. Now the 21-year-old is the world's best /

The 21-year-old said he took the first 50m "easy" before bursting back along the home straight "with everything I've got".

He told Sky News: "I didn't do it for myself, I did it for my country.


"I trained my mind so well, I feel like I've swam that race a thousand times in my head. I never thought it could work out this well."

Team GB Celebrates Peaty's Gold

Cameron Van der Burgh of South Africa won silver while Cody Miller of the United States took bronze.

In the next race, minutes later, fellow swimmer Jazz Carlin took silver for Team GB in the women's 400m freestyle final.

Four years ago, the 25-year-old from Swansea was heartbroken after missing out on selection for London.

Image: Jazz Carlin posted a Snapchat photo of herself and Peaty

Looking visibly stunned, she said: "I honestly cannot believe it - I'm on the edge of tears. I'm so happy."

She was beaten by American Katie Ledecky, who won gold in a world record time of 3:56.46 seconds.

Peaty's gold is the first by a male British swimmer in 28 years, since Adrian Moorhouse's success in the same event in Seoul 1988.

Image: Peaty's parents celebrated with his girlfriend Anna Zair

A surprise star of Peaty's story has been his adoring grandmother, Mavis Williams.

She roared him on in the early hours of Monday morning from her home in Uttoxeter, Staffordshire, and tweeted: "Well you have done it @adam_peaty you have made it, your hard work paid off.

"So proud love Nan x"

Peaty joked: "It took me so long to get 3,000 followers on Twitter and she got it overnight. She's never doubted me, and that means so much to me."

#OlympicNan Wins Twitter

The Team GB medals take Britain to eighth in the table.

The US leads the table with 12 medals followed by China with eight and Australia with six.

Elsewhere, there was drama in the men's tennis as Team GB brothers Andy and Jamie Murray were knocked out in the first round of the doubles event.

Image: Lizzie Armitstead came fifth in the cycling road race

The second-seeded pair lost 7-6 7-6 to the Brazilian duo of Andre Sa and Thomaz Bellucci.

But Andy did manage to ease past Viktor Troicki as he got the defence of his Olympic men's title under way.

In the cycling, Lizzie Armitstead - competing after controversy over missed drugs tests, could only manage fifth in the women's cycling road race.