Urging them to vote against the polling method that would be introduced under the European Parliamentary Elections Bill, the MP for Chesterfield said that no traditional Liberal would look twice at such a system because they had always been advocates of "being free from the party".
Speaking during a debate to overturn the third government defeat by peers over the system, Mr Benn said: "But of course they have been given a job... Part of the deal is you go along with us and we give you a bit of useful work."
Opening the debate, Jack Straw, the Home Secretary, dismissed the "constitutional ping pong" with the Lords as "politics of absurdity" and a "determination" by unelected Tory hereditary peers "to override the elected will of the ... Commons".
The Bill goes back for a fourth time to the Lords today and there could be a danger of it being lost if no compromise is found until Parliament prorogues on Thursday.
Mr Straw accused Tory hereditary peers of opposing the "elected will" of the Commons and renewed his offer to review the disputed system after next June's Euro election.
Peers have objected that closed lists were undemocratic because they put too much power in the hands of the centralised party machine. Mr Benn said the arguments against the closed-list system were "absolutely overwhelming".
Quoting from "five democratic questions" he had developed in his political career, Mr Benn added: "If you meet a powerful person it might be Rupert Murdoch, it might be Joe Stalin, it might be Hitler ... Ask them five questions - what power have you got, where did you get it from, in whose interests do you exercise it, to whom are you accountable and how can we get rid of you. If you can't answer the last question, how can we get rid of you, whatever the merits, you do not live in a democratic system. I am genuinely alarmed at any party seeking to impose candidates."
Richard Allan, for the Liberal Democrats, said his party would not oppose the closed-list system as it believed that if the Bill was lost, Liberal Democrats risked being left with the old first-past-the-post system.
He said: "The first-past-the-post system, which we believe is the alternative ... if we are not able to resolve this dispute tonight and actually get some agreement, would take us a step significantly further back."Reuse content