LUKE Shriever admits it's "quite mad" thinking that he's the planet's best BMX racer in his age group, but he'll have to get used to it after his stunning victory at the UCI BMX World Championships in Colombia.

The youngster from Finchingfield blitzed the best riders from across the globe to take the boys' 13-years crown in Medellin and there was further joy for the Shriever household as Luke's 16-year-old sister, Bethany, came home from Colombia with a World silver medal in the Junior Women's category.

Luke came through the rounds strongly around the technical Medellin circuit and held his nerve with a peerless ride in the final.

He finished third in the World Championships in Belgium in 2015 and is reigning European boys' 12-years champion, but he latest success is a huge step and he admitted it had been taking some time to sink in that he would be sporting the W1 plate on the front of his bike for the next 12 months.

He said: "It's quite mad really, thinking that I'm the best in the world in my age group.

"It hasn't really sunk in yet, but it's pretty cool.

"It's what I've been aiming for for the last year after coming third in 2015 as I felt then that I could do better."

There was also delight for his older sister in Colombia, although Bethany said her joy at claiming a World silver medal in the Junior Women's time trial was tinged with disappointment after crashing out in the final of the championship class racing.

She was one of three athletes hand-picked by British Cycling to compete at the highest levels in Medellin and repaid their faith on her first Junior Women's appearance with some superb displays against girls who were racing for a second year in that class.

Bethany set a stunning pace in the time trial and was only pipped to the gold medal by less than four-tenths of a second.

That gave her confidence for the championship class racing and despite being one of the younger racers in the event, she progressed sublimely into the final and was looking one of the favourites for not just a podium finish but to claim a coveted rainbow jersey as world champion.

There was disappointment as she crashed out early in the final, but Bethany said she would take plenty of positives from her experience.

She said: "It was a great experience for me and to come away with a silver medal from the time trial was a highlight, but I was aiming to do better in the racing.

"I was devastated to crash out on the first jump and so disappointed.

"I felt really good through the day and my mindset was positive so that when I went out in the final I was determined to get the rainbow jersey.

"But I have to come away, look forward to (the World Championships in) Rock Hill next year and take the positives from it.

"It just helps with experience for the future so as I move up into the elite group I'll be more prepared for events like that and better able to deal with the pressures you get there."