YOU’VE got to hand it to these boys – they are very, very brave.

Nothing stands between them and crazed hordes of baying little girls with painted claws and unchecked hormones.

Parents are keeping a safe distance on so many picnic blanket islands scattered across this forest-encircled field at Westonbirt Arboretum.

Two of the four bands, Louis Walsh’s latest Irish sextet Hometown and British boy band Union J, don’t even have anything to hand for self-protection – only headliners The Vamps and their American proteges, The Tide, play their own instruments.

All the lads can do to prevent a sudden stage invasion is keep their (honestly) constantly screaming young fans dancing, and to this end one high energy number after another does the trick just fine.

The warm-up acts do a more than creditable job, particularly The Tide who succeed in bewildering the girls with a fast-paced acrobatic routine. Then it’s the turn of The Vamps, who really crank up the action.

These talented young musicians - Brad Simpson (lead vocals and guitar), James McVey (lead guitar and vocals), Connor Ball (bass guitar and vocals) and Tristan Evans (drums and vocals) – are a YouTube success story. Their cover uploads gained them an overnight army of followers and led to a quick signing with Mercury Records in late 2012. Since then they have supported ever bigger acts, from McFly and The Wanted to JLS, Little Mix, Lawson, Demi Lovato and Taylor Swift. Now it’s their turn to front a world tour, and they are fresh back from sell-out shows in Japan, the Philippines and Australia; following their Forest Live appearances they embark on a US tour next month.

Covers remain a strong feature of their increasingly diverse repertoire. Their Uptown Funk rendition and 7 Nation Army (The White Stripes)/Shake It Off (Taylor Swift) mash-up are superb, as is their take on the Simon and Garfunkel classic Cecilia and My Chemical Romance’s Teenagers, Miley Cyrus’s We Can’t Stop and Sum 41’s In Too Deep.

But it is their growing list of original numbers that is establishing The Vamps as a force in their own right: the 2014 World Music Awards saw them nominated across all top categories (Best Song/Best Video: Can We Dance; Best Song/Best Video: Wild Heart; Best Album: Meet The Vamps; Best Group and Best Live Act). Their Westonbirt set included Hurricane, Somebody To You (their new Demi Lovato collaboration), Last Night and Move My Way. Highlights were Tristan’s spectacular drum solo over RnB mixes (N-Dubz and Flo Rida); and a sublime, ultimately hysteria-inducing guitar and vocals performance from lead singer Brad with Shout About It.

Miraculously, no boys were harmed in the making of this concert.

- BIANCA POLIZZI