It's Northern swagger versus London's favourite diva in the battle for this year's Nationwide Mercury Prize.

Arctic Monkeys and Amy Winehouse head the contenders among the 12 albums in the running for the £20,000 prize, unveiled in London today.

The Arctic Monkeys could become the first act to scoop the award twice - and in consecutive years. They won last year with their debut album Whatever People Say I Am, That's What I'm Not.

This year they are contenders with their follow-up, Favourite Worst Nightmare. Winehouse is nominated for the second time for her album Back To Black.

The bookmaker William Hill immediately installed Winehouse and Arctic Monkeys as joint 4/1 favourites.

Dizzee Rascal, who won the prize in 2003 with debut Boy In Da Corner, is nominated again this year for Maths And English.

Other contenders include The View, Klaxons, Bat For Lashes and Jamie T. The prize is open to British and Irish acts who have released an album in the past year and covers all genres of music.

Last year the Mercury judges surprised many by going for the "people's choice" in Arctic Monkeys. Industry experts predict the judges may revert to type by choosing a more obscure act this time.

Gennaro Castaldo, from HMV, said: "It will be interesting to see if the judges are prepared to open themselves to potential accusations that they are going too mainstream by voting for the Arctics for a second year in a row or by selecting Amy Winehouse - both of whom have enjoyed massive commercial success - or whether they deliberately go for a less obvious choice in order to show that they remain unpredictable and independently minded.

"You'd have to say this is a fairly well-balanced list, which reflects the diversity and vitality of the British and Irish music scenes right now."

Inclusion on the shortlist means a sales boost for the lesser-known nominees. The prize has been running since 1992 and past winners have included Primal Scream, Suede, Pulp, Ms Dynamite and Franz Ferdinand.

The 12 nominated albums are

Arctic Monkeys - Favourite Worst Nightmare

Amy Winehouse - Back To Black

Dizzee Rascal - Maths And English

The View - Hats Off To The Buskers

Maps - We Can Create

Bat For Lashes - Fur And Gold

Klaxons - Myths Of The Near Future

Jamie T - Panic Prevention

The Young Knives - Voices Of Animals And Men

Fionn Regan - The End Of History

Basquiat Strings with Seb Rochford - Basquiat Strings

New Young Pony Club - Fantastic Playroom

The winner will be announced at a ceremony on September 4.

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