The crowd gathered inside Rock City tonight is a very odd mix.

While fifty per cent of the obvious gig regulars make their way systematically from the merch window, to the bar before barging their way to the front of the stage, there is another breed of music fan struggling to find their feet.

“Well this isn’t what I expected,” one woman gasps as she makes her way through scores of fifteen-year-old girls. “I mean, where are the seats?!”

The truth is - whether they want to admit it or not - Plain White T’s have scored a massive mainstream following after the release of the summer hit Hey There, Delilah. With claims from critics that they’ve sold out on their early roots, they’ve got a lot to prove on this tour.

To boost their chances they’ve brought some top-notch support acts along on tour to help win even the harshest of cynics over. First up, Georgia-USA five piece Cartel take to the stage with their catchy-as-hell brand of power pop.

Blasting through tracks from debut album Chroma as well as their self-titled follow-up, it’s obvious that Cartel are impressing both newcomers and existing fans. Runaway gets a corker of a sing-along from the middle of the crowd, and by the end of the track, even those of a more nervous disposition are bopping along at the back.

However, its closing tracks Say Anything (Else) and Honestly that get the night underway properly, both with epic riffs and sing-along lyrics. From this performance, its safe to say that Cartel will head back to the States after this tour with a few more fans this side of the pond.

Next up are Boys Like Girls with their cracking brand of power-pop. Opening track Hero/Heroinesees the majority of the crowd descend into a chaotic mix of singing, dancing and shoe throwing, and the energy levels rarely drop throughout the set.

Last in the UK in April 2007 for the Give It A Name festival, the room erupts as the five-piece blast through their set. These guys have toured with the likes of Motion City Soundtrack and The All-American Rejects, and it’s easy to see why.

“Have you brought your dancing shoes?” lead vocalist Martin Johnson asks, “’cause you’re going to need them!” As the slightly grungier Dance Hall Drug kicks in, the crowd are more than willing to oblige, and the floor of Rock City erupts. With its sweet sing-along chorus placed alongside dirtier-sounding verses, it’s aptly the track that gets the most people on their feet.

Showing they’ve got a few more strings to their bow than catchy dance-floor tracks, the mood drops for a slight rework of fan-favourite Thunder. Performed for the most part as an acoustic track, Johnson captivates the room single-handedly with his cracking combination of tenor and falsetto vocals. At times it’s hard to understand how one person can produce such different sounding sounds. But it works.

Upbeat pop returns to end the set, with the catchy-as-hell The Great Escape chosen for a closer - and definitely a track to be considered for the band’s first UK single later in the year.

A little behind schedule, headliners Plain White T’s finally hit the stage a little after 9.30. Kicking things off in spectacular fashion with current UK single Hate (I Really Don’t Like You), the band barely stop playing over the course of the sixteen-track set.

Three tracks in and the room goes nuts for the slightly cynical Friends Don’t Let Friends Dial Drunk. Lead vocalist Tom Higgenson proves himself a great showman, parading the stage with drama-filled poses and seemingly endless energy.

Asking how many members of the audience tonight have their first album, Higgenson dedicates cute acoustic number A Lonely September to ‘all the old-school fans’, While a few groups join in, the majority of the crowd have to settle for arms-in-the-air action alone. For those ‘old-school fans’, it’s a nice touch to remind them that they’re still remembered after …Delilah.

A near-fail sing along for Our Time Now means the ultimate insult is made on the Rock City faithful: “What was that?!” Higgenson laughs. “You’re not as good as London….”

His trick works, and the catchy oh-oh-oh-ohhhhhs are returned to him at a deafening rate for the rest of the song. As the Plain White T’s depart the stage, the gig first-timers at the back look worried that they’ve spent eleven quid and are going to go home without hearing their beloved summer ballad.

Returning to the stage to chants of their name, Plain White T’s of course oblige to their request and knock out a beautiful rendition of the number one single. The night is brought to a close with Take Me Away. Cynics will tell you it will increase record sales of previous albums. Fans will tell you it’s to make them feel special. Either way, it’s a fine choice to close the night on.