Neil Kinnock, leader of Britain's opposition Labor Party, will be challenged for the post by veteran leftist Tony Benn at the party conference in the fall, a Labor coalition said Wednesday. The Campaign Group, composed of about 40 leftist party lawmakers, said Kinnock's deputy, moderate Roy Hattersley, will be challenged by leftist Eric Heffer. The announcement came after a meeting of the party's national executive committee. Kinnock, 46, and Hattersley are considered not as left wing as Benn and Heffer. Benn, 62, a former Cabinet minister, has accused Kinnock of watering down socialism after the party's three defeats in nine years by the Conservative Party of Prime Minister Margaret Thatcher. Kinnock and Hattersley have worked for a united party and cracked down on militants in hopes of making a broader appeal to voters. They say a leadership contest will distract the party from opposing the government. Kinnock and Hattersley denounced the challenge in a joint statement as ``futile and selfish'' and predicted ``massive defeat'' for Benn and Heffer. Benn told reporters: ``Democracy is about choice.'' Heffer said: ``The time has come for a crusade for socialism. The working people of this country are getting a worse and worse deal.''