The wordy talents of Isaiah Hamilton – aka Lil Dreads and, more recently, Isaiah Dreads – have been well known in and around Dorchester for several years.

But after this summer the teenage rap artist is set to ‘go global’ thanks to performances at three of the UK’s most popular music festivals.

When we meet, Thomas Hardye School pupil Isaiah is fresh out of a science GCSE and is, understandably, rather thoughtful and subdued, slumped on his mum’s living room sofa in his school uniform.

But put him in front of an audience and the dreadlocked 15-year-old switches persona and becomes a full-on star sparking with charisma, his mega-watt smile and adolescent confidence lighting up the venue.

“The bigger the crowd, the more I enjoy it,” he said.

“I don’t like playing to a small crowd when there are just a few people dotted about. When there’s big crowd it’s like everyone is there together, having a good time together. That’s what it’s all about.”

This is just as well, because this summer will see Isaiah performing at Glastonbury, Bestival and Camp Bestival here in Dorset.

Word of Isaiah’s prodigious talent has also filtered out into the wider music universe and producers and record labels have started to sit up and pay attention.

Angus Baskerville, an industry-famous agent with 13 artists who represent a broad range of artists such as Radiohead, Arctic Monkeys, Maximo Park and Paolo Nutini has said ‘it’s not a case of if Isaiah is huge, but when’.

Recognition is there from million-selling artists too. The chart-topping American rapper Nikki Minaj found one of his videos on YouTube and raved about his music and dreadlocks, leading to 2,000 ‘friend’ requests on his Facebook site in half an hour.

The Glastonbury gig came around after he was one of 12,000 entrants for the festival’s Emerging Talent Competition. Although he didn’t win – that honour went to Bridie Jackson and the Arbour – festival organisers approached him and asked him to join the playlist.

He will be performing in the festival’s Silver Hayes Dance Village and Pussy Parlure areas and will also play backstage for the entertainment of other acts which include The Rolling Stones, Example and Primal Scream.

His slots at Bestival and Camp Bestival came about through some good old-fashioned hustling.

“I messaged and tweeted them, saying I would love to play but they replied that they had no space left,” said Isaiah, a quietly-spoken lad who has been played on Radio One by the festivals’ founder DJ Rob da Bank.

“Then when I Tweeted that I was playing at Glastonbury they messaged me and after putting me in touch with a couple of people I got those slots too.”

He added, with typical teenage insouciance:

“Glastonbury will be so cool. I can’t wait to see The Rolling Stones.”

Isaiah grew up in a household where music played constantly. He wrote his first song aged six, made his first recording at nine and released his first CD at 11.

The first taste of fame came in 2009 when he wrote the winning rap for the government’s national anti-knife crime competition It Doesn’t Have to Happen to You. Under the alias of Lil Dreads, he was awarded a gold Blue Peter badge, appeared on the BBC’s Newsround bulletin and attended a Radio 1XTRA weekend where he got to hang out with some of his musical heroes.

After this success he began to perform locally and is now on the playlists of national radio DJs, while more seasoned performers request him as a warm-up for their act.

His latest local appearance was at Airfest on Weymouth Beach, when crowd control became something of an issue.

His mum Amanda Sappleton, a former nurse who acts as Isaiah’s driver, manager, PA, caterer and security when she’s not looking after his younger brother Eli, said: “It was mad, all these girls screaming and trying to jump over the fence. After his set he had to be escorted off-stage by security. We waited a couple of hours before we got the train back to Dorchester and even then when we left there were girls chasing us along the beach, asking Isaiah to autograph their arms and legs. It was unbelievable!”

As well as performing, Isaiah writes, develops and produces all his own music and oversees his videos, which can be seen on YouTube. The film for his latest release Say Yeah was made in Puddletown and Puddletown Forest and involves the musician declaiming his thoughts while riding a mobility scooter that eventually ends up in a stinging nettle patch.

The next hurdle for Isaiah will be the balance between music and the looming presence of GCSEs – there were fears at one point that one of his science modules might have clashed with Glastonbury, which almost led to ructions over a difference in priorities between Isaiah and mum Amanda.

The main bulk of GCSEs come next year, with music production being one of his options. But what does Thomas Hardye’s music department think of his success and forthcoming Glastonbury appearance?

“They didn’t know!” exclaimed Amanda.

“We had parents’ evening at school and his music teacher said ‘is there anything you need to tell us Isaiah?’ and Isaiah said he didn’t think so, so his teacher said ‘about Glastonbury?’ He’s so laid back he’s practically horizontal!”