The Thomas Cowley High School flier went unbeaten on the boards this winter, topping off a fine series of victories with gold in the 400m at the England Athletics Under-17 Championships in Sheffield in March.
Sandall said: “I was delighted with how I performed and I couldn’t really have asked for more.
“Running a personal best of 49.14 to take a national championship title and keeping my UK number one ranking was a great way to finish the indoor season.
“I started training last October and set myself the goal of getting a medal at the nationals.
“But I exceeded all expectations in Sheffield and the 400m gold was the one that topped it off for the whole indoor season.
“For the final, my coach Dave Clay told me to lead from the front so as to make it very difficult for the other athletes in the race to pass me.
“The national title has changed my outlook on athletics dramatically and now I am training hard for the outdoor season.”
Ever since the Flying Scotsman Eric Liddell won Olympic gold at the 1924 Paris Olympics, British runners have excelled over the 400m distance, whether on the flat or over hurdles.
The top ten British 400m runners of all time includes former Commonwealth and European champion Iwan Thomas, Olympic and World Championships silver medallist Roger Black and Derek Redmond, who was part of Britain’s the 4x400m relay squad which won gold at the 1991 World Championships in Tokyo, Japan.
Sandall added: “I used to be a footballer through and through but at the end of Year 8, a friend of mine said that his coach was looking for someone to run the 200m.
“Before I got into athletics, I hardly followed it all but after I tried it, I joined Nene Valley Harriers a couple of years ago and they’ve helped me get to where I am now.”
Sandall’s trophy cabinet so far includes three Lincolnshire Schools Championships gold medals over 200m and 400m, three Lincolnshire County Championships gold medals for the same distances and a collection of Anglian Schools Championships and Northern Under 17 Championship golds.
“I train two or three times a week at home, doing a lot of exercises, a few weight training sessions and a couple of two-mile runs,” he said.
“Injuries have been a hindrance because I’m growing very fast but, although it’s frustrating at the time, my coach says I’m not losing any ground to my rivals.
“My target this season is to qualify for the World Junior Championships (in the USA) next month and hopefully break the 49-second barrier this summer.”
Sandall’s name is already engraved on the Thomas Cowley High School roll of honour after breaking the Year 10 boys’ 200m record that had stood since 1970.
But he knows that this offers no guarantees when it comes to his GCSE studies and his plans to study sports science.
He said: “I try to work hard at school, but I also enjoy training and I want to see where my athletics goes first.
“I’ve been running at senior level for Nene Valley Harriers since 2013 and I’m pretty sure that I’m the youngest person competing in the British Athletics League.
“But my aim is to make it to the top and the focus is on achieving that.”