Entering a hotel room to meet all five of them, then, might seem like walking into a viper's den of candid opinion and lairy behaviour, but the truth is much more civilised than that. It almost always is.

Lounging around on sofas having just finished their lunch, the girls are the picture of normality. Dressed casually and chatting enthusiastically among themselves, they could be any quintet of close friends at a sleepover or similar girly gathering. They're all gorgeous too, somehow even prettier in the flesh than the countless airbrushed images of them that have adorned many a glossy magazine since they formed five years ago.

Surprisingly, as Kimberley explains, they were feeling nervous ahead of the release of their fourth studio album.

“Because things have gone so well for us, we want to keep that level up and improve if anything” 

"It's not a new thing, we get nervous about everything," the Bradford-born lass says. "We just still really care. Everything has gone great so far, but we still worry. Because things have gone so well for us, we want to keep that level up and improve if anything. That's quite a high expectation, so we end up putting a lot of pressure on ourselves."

It's immediately clear after meeting the girls that each member brings something very different to the band.

Kimberley is the wisest and most mature, offering reasoned and articulate answers to whatever question thrown her way, while Nadine - wearing small shorts and voluminous hair while the others are tracksuited and ponytailed - adds glamour. She's also famous in the States, thanks to her high-profile relationship with Desperate

Housewives star Jesse Metcalfe. She owns a chain of restaurants there, and property in LA.

Cheryl, married to Chelsea defender Ashley Cole, is blessed with a steely attitude and a quick wit - not to mention a diamond ring as big as a house - and 'Scouser' Nicola (she's actually from Runcorn inCheshire) has a bone-dry humour, sometimes mistaken for her being moody or sullen.

Sarah, meanwhile, is asleep under a pile of coats for most of our interview and is lost behind her outlandishly sized shades. Maybe she's ill, maybe she's hungover - either way, she certainly adds the rock'n'roll element missing from most girl bands.

This new album then, Tangled Up...nitely. Less tongue-in-cheek," adds Sarah, briefly lifting her head from her slumber.

All five members are united in praise for recent single Call The Shots, while Can't Speak French, rumoured to be the next release, is a particular favourite of Cheryl's.

"It gives me goosebumps that song, I love it," she beams. "I can't speak French although I did go out with a French boy for a little while, so I got some CDs to learn the language. I picked up a bit, but I've forgotten apart from a few bad words."

The album also features a number of songwriting credits for the girls, building on the handful of B-sides and album tracks they've contributed to in the past.

"We never got into this industry to be brilliant lyricists," says Cheryl, "but recently we've felt more comfortable with writing bits and pieces. Sometimes you just have to let people do what they're talented at, and stick to what you know best.

Thrown together as winners of Popstars: The Rivals, the girls soon gelled as a band and have gone on to break chart records. When their last single Sexy! No No No hit the Top 10, they also entered the Guinness Book Of Records as the most successful female group in UK chart history.

The song was their 16th consecutive song to hit the Top 10, smashing the previous standards set by Destiny's Child and GA's spiritual mothers, the Spice Girls. It's only fair really, as neither of those bands had a song to come close to the pop perfection of Biology either. Or No Good Advice, The Show, Something Kinda Ooh and Love Machine for that matter.

Such success does have it's downsides, however. Namely being pursued by mercenary photographers on a daily basis. You won't hear the girls moaning about it, but that's not to say they like it.