There were cheers and tears as six-year-old Jack Rickard astonished onlookers by completing a 2.5km fun run in less than half an hour.
Jack, who suffers from cerebral palsy, was determined to complete the course to help raise cash for a life-changing operation.
Lining up alongside Jack on the start line of the event, at Barnack Primary School on Saturday, were his twin sister Ava and parents Steve and Shona.
It was thought it might take Jack several hours to finish the race - but he astonished everyone by getting round in just 28 minutes.
Shona said: “I was so proud of Jack I had tears in my eyes all day. He was simply amazing. It was a show of pure determination.
“He kept saying ‘I want to run it’ and tried to jog holding his dad’s hand.
“He took a couple of brief breaks, but with Ava’s encouragement he was soon over the finish line.”
Although the total amount raised by Jack is still being added up, it will be more than £1,000 and the final figure will be matched by Stamford XT - an association of former Round Table members.
Jack’s parents are trying to raise £60,000 so he can undergo surgery at Great Ormond Street Hospital in London.
The procedure, Selective Dorsal Rhizotomy (SDR), could remove the majority of spasticity in his legs, giving Jack the best chance of living an active life.
But the operation it is not currently available on the NHS, so a series of fundraising events have been planned to pay for it.
On Sunday the appeal - called Jack’s Journey - was given another boost when a fundraising parachute jump took place at Sibson Airfield.
Matt Tyers, 41, whose son Noah goes to Barnack Primary School with Jack and Ava, took the plunge from 13,000ft while strapped to an instructor.
Matt raised £1,400 - with £500 of that coming from the Lindum Group, where he is group engineering director.
He said: “I know the Rickard family well and was more than happy to volunteer for the jump when I heard they were looking for people to do it.
“It was an honour to take part for such a great cause and I was lucky with the weather which was absolutely perfect.
“We were freefalling for about a minute before the chute was pulled.
“I did the easy bit. What Jack did at the fun run was amazing.”
Jack was on hand to give Matt a big hug when he landed safely.
If you would like to donate to Jack’s Journey, you can do so via www.justgiving.com/jackrickardsjourney
UK Parachuting, which runs Sibson Airfield, is happy to hear from anyone else who would like to do a jump for Jack’s Journey. Visit www.skydivesibson.co.uk