The all-girl folk quartet, famous for singing in their gorgeous Geordie accents, are back with The Bairns, the follow-up to 2005’s Cruel Sister, which received a hearty thumbs up from folk purists and mainstream radio alike.

How do you follow up a successful crossover folk album like Cruel Sister? The Bairns is a bit different to Cruel Sister because we have become a lot tighter as a band and we have a new fiddle player, Niopha, who has added a slightly different sound. I did a bit of research into Northumbrian songs – sea songs and border ballads – it’s quite important to us to represent our tradition. If you’re Scottish or Irish it’s easy to get excited about your own folk culture but a lot of English people aren’t aware that they have all this great folk music that they can feel good about.

You seem to have invented a new instrument on The Bairns called ‘feet’. It’s something that we developed in our live acts. Becky and I grew up in a clog dance team and our dad is a Northumbrian rapper sword dancer. We wanted foot percussion but the clogs were too heavy. Becky was clipping around in her heels one day so we decided to introduce the ‘high-heel tap’ into folk music. It adds a bit of glam. It also gave us a great excuse to buy lots more shoes.

The Bairns is a mix of traditional songs and a few covers. Was it difficult to strike a balance? Folk songs only become folk songs when folk sing them. ‘I See a Darkness’ by Bonnie Prince Billy is a van favourite of ours, it’s on all the time, and ‘A Minor Place’ sounds like a folk song to me. We’ll try anything we like really. I love a song that tells a good story.

The Bongo Club, Edinburgh, Fri 14 Sep; the Arches, Glasgow, Sat 15 Sep.