Labour rebels claimed yesterday that up to 160 backbenchers will vote against Tony Blair if Britain launches an attack without a fresh UN security council resolution. Amid a growing belief that Robin Cook is planning to resign from the cabinet, a leading rebel predicted that the 122 Labour MPs who voted against the government last month would be joined by a further 40. MPs are expected to vote on Iraq, possibly as early as tomorrow, after the failure of Britain to secure a second resolution. Tony Lloyd, a former Foreign Office minister, told Radio 4's The World This Weekend: "I...