A nine-year-old inventor's silent robotic bird scarer has won a farm innovation award at the Royal Norfolk Show.

Robert Mumford, from St Neots in Cambridgeshire, won the "new ideas" prize for non-members, run by the Norfolk Farm Machinery Club (Normac).

His satellite-guided "Ro-Bert" machine scatters flocks of birds by moving autonomously across fields to pre-programmed positions, triggering the movement of a model boy in a flat cap with a shotgun - based on a photo of himself.

The crop protection idea sprang from local frustration at the use of noisy gas cannon bird scarers, and was built with the help of his father William, an arable farmer at Agden Green Farm.

The young innovator, who was allowed a day off from Kimbolton School to collect his award, said: "There are different waypoints that it is programmed to go to and stop, and then it moves the gun up and down to scare the birds away.

"We did have an idea that you could sit on it and drive it, but then it doesn't work because it blows the fuse."

His mother Emma said: "We're very proud. It was a Christmas project to get him off his iPad and into the workshop.

"The idea popped up in the winter. All the gas guns were going off in the village so the Facebook page was going mad with people saying: What's that noise, why is this going on? It's scaring the dogs, why can't you make a silent one?"

The members' category of the contest was won by Henry Stanford from Reymerston for his tool to ease the process of pushing pegs into the ground around newly-planted trees, and the prize for commercial manufacturers went to G-Tec trailers for a 1,000-litre drinking water bowser with a "wide application on farms that are expanding into livestock for reasons of soil health".

Other innovations on show included a pig vaccination unit designed by Harry Wiseman from Beeston, and an "ingenious" mini hay-baler made by Matthew Harrold of Barnham Broom.

Normac county organiser Chris Thomas said the competition proved the spirit of agricultural innovation is thriving in Norfolk.

"As you can see we have got a huge variation in ability, and what people want from their machinery," he said.

"You've got stuff which is very basic, and other bits of kit are really well made and could easily be manufactured.

"Every farm is different and every requirement is different, so everyone adapts their machine in the end."

Mr Thomas was overseeing the club's show stand for the last time before his retirement next February. "We have had some wonderful years up and it has been a pleasure to organise things," he said.