PJ Harvey throws out 75 per cent of the songs she writes.

The 'Written on the Forehead' singer - who became the first artist to win the Mercury prize for the second time earlier this week, for her eighth album 'Let England Shake' - rejects a lot of the material she initially writes, to avoid repeating herself.

She told The Times newspaper: "I could too easily write the same record again and again, so if I realise a song is similar to something I've already done, I throw it out.

"It gets harder as I get older because I have to write a lot more material and end up throwing out seventy five percent of it.

"It's hard to not do what comes naturally. But you have to challenge yourself."

PJ -full name Polly Jean Harvey - wrote 'Let England Shake' about war and conflict around the world and through history, and while she spent a great deal of time researching it and over two years writing the lyrics, she didn't rely on the internet.

She added: "I use the internet very, very rarely, and then only for some specific piece of research. It's too much information for me. I'd rather work with a limited amount of material and allow myself to explore that than be saturated with things that would dissipate my concentration."

'Let England Shake' is out now.