An MP has announced she will step down at the next election after ‘something broke’ in her when her party responded to concern about welfare by backing a cap on benefits.

Sarah Teather, Liberal Democrat MP for Brent Central, announced on Saturday that she will not be seeking re-election at the next General Election in 2015.

Speaking to the Observer, she said she believes the £26,000-a-year limit will not work and is a political stunt. She said it will affect many of her constituents in the ethnically diverse constituency of Brent Central and they may be forced to leave their homes to seek work in cheaper areas where fewer jobs would be available.

“It was the moment of realising that my own party was just as afraid of public opinion as the Labour party,” Miss Teather, the youngest MP to ever be elected in 2003, said. “Something did break for me that was never ever repaired.”