Our daft name is the monkey on our back

Well that's a bit like how Nat Johnson, chief whip, writer and singer of Monkey Swallows The Universe feels about her band.

"It is a bit annoying because it was only a stupid joke name. Had we known this would turn into something..." she says.

"Now it's like one of those Marmite situations. But I guess lots of bands have got rubbish names and we don't hold anything against them, so if someone is going to do that to us I don't care if they like us or not."

When Nat did suggest swapping their handle for something more sensible her four colleagues said a defiant 'no'.

"I did want to change it about a year ago, to The Menders. The others said no, probably because they thought it was too late."

Which is a fair point, what with their second album, The Casket Letters, out on Monday. Plus the reference to the '80s martial arts series Monkey is possibly slightly more interesting than the name used for their first gig together, Something About Jack, what with that sounding a tad like a Hollywood comedy involving someone called Mary.

That said there's a connection there between the album and Mary, Queen of Scots, that is. And their hometown Sheffield, although not everyone realises said royalty was imprisoned here. The 'letters' were used against her by supporters of her cousin Queen Elizabeth.

"It is something I find interesting and I find it provides a bit of mystery as well as a Sheffield connection. This album is a bit darker and I already had a song in mind for it, called Elizabeth & Mary. And sometimes it is a good thing to have to dig deep rather than have it all on the surface.

"But inspiration comes from anything. We've got some stories that are true, some are totally random, sometimes they are fantasy. We don't stick to any rigid rules so I really let songs write themselves; what comes out comes out."

Besides the album title, current single Little Polveir also comes with a yarn. In fact, it led to their deal with London indie Loose who had watched with interest the fuss made of MSTU's debut album The Bright Carvings.

The song is named after a Grand National winner with strong connections to the label's boss. "The head of Loose is married to the daughter of the trainer of the horse," confirms Nat. "If we had not had that horse single... well, that was the clincher. Actually he had been looking at us for a while, but it was a complete coincidence.

"The photo on the cover came from the owner of the horse which was the first horse I won money on. I was nine at the time. I had backed it a couple of times before and it never won. So when it did it was quite a big thing. It's name is a reminder to me to persevere – with bands it is sometimes a little bit hard going."

Putting their money on Little Polveir seemed to do the trick again as the single has turned MSTU on to a wider audience, drawing unlikely praise from The Sun and the Daily Telegraph which profiled Polveir on its sports pages.

That could spell even busier times for Nat, a PA with Sheffield Children's Hospital, and band mates Kevin Gori, Cate Tully, Andy George and Rob Dean. In The Casket Letters they've taken their trademark mix of occasionally haunting folk pop and acoustic lushness and fattened it, matching the delicate with more robust melodies and finding darker corners as well as optimistic ledges. It's their most commercial music yet.

"We're doing everything we can to get around the country as much as we can and trying to fit our lives around it.

"All the while people are saying nice things about us we might as well," says the 27-year-old singer.

"It is hard to stand back and see how other people might see us. We just want to write some decent pop that's not stupid but also not take ourselves too seriously and go on about northern life. At the moment we have a broad appeal."

One thing MSTU have been proving is there's room for more than one band from Sheffield with primate links, even if their sound is polar opposite.

"Some people, if they don't know anything about us, think we put monkey in the name to get something off the back of them (Arctic Monkeys)," says Nat. "I'm pretty sure we had it before them.

"Anyway, we just want to keep doing what we have been doing a bit better each time, play abroad a bit more, meet lots of people... and have a really good time."

Tomorrow they launch the album at Sheffield's Merlin Theatre with unlikely support from Viarosa and Smokers Die Younger, bringing in violins and Nat on guest vocals. MSTU also play The Lantern, also Nether Edge, on November 4.