Kennedy will call on Blair to honour his promise on PR

Charles Kennedy will issue an ultimatum this week to Tony Blair to honour his commitment to review the introduction of proportional representation.

The Liberal Democrat leader will use his conference speech to scotch talk that his party has given up on electoral reform. He will tell Labour to stick by a manifesto promise to review the voting system after the local elections next year or jeopardise relations with his party.

Mr Kennedy is said to be worried that Labour is backing down on the issue in the face of opposition from grassroots activists and the trade unions. Sources close to the leader said Labour was hoping reform would be "swept under the carpet" and incorporated in a wider review of policy that would not lead to any concrete proposals or action.

Mr Kennedy will indicate in his speech that his patience over Labour delays on PR has run out. "He is not going to let Blair off the hook on this," sources said. "He is very, very serious about holding the Government to account over their commitment."

Today Labour and the Liberal Democrats in Scotland are expected to announce a deal on a new voting system for local government based on proportional representation.