The Green Party must not pick a permanent leader if it is to maintain its "refreshing distinctiveness", its annual conference has heard.
Mr Wall said having leaders could corrupt parties
Principal speaker Derek Wall said the Greens should not be "sucked in" to having a figurehead like other parties.
The Green Party in England and Wales has one male and one female principal speaker, rather than a single leader.
Some members believe this should change, in an effort to make policies better known to voters.
But Mr Wall said other parties were "increasingly seen as bunches of liars, hypocrites and suits on the make".
He accused Labour, the Conservatives and Liberal Democrats of having "painted-on environmentalism", as they were united in the "insanity" of pursuing "ever-increasing economic growth".
Mr Wall called for cheaper public transport and for the UK's nuclear weapons system not to be replaced.
He also condemned the use of carbon-offsetting schemes as ineffective and challenged all environmentalists to give up flying.
The Greens, who have two MEPs and close to 100 local councillors, elected Sian Berry as their female principal speaker last year.
Critics say this system restricts the party's effectiveness.
But Mr Wall said: "I do think being called a leader has the potential to corrupt.
"I look forward to being replaced as principal speaker by someone better but I will mourn if speakers make way for old-style, ego-led political figures.
"I have no easy answers, I won't tell you any comforting lies but I know my history and I can recognise a trap however well disguised."
Mr Wall told party delegates in Swansea: "Virtually every radical movement in history has been sucked in and domesticated.
"Socialism led to Stalin and Tony Blair. The Romans deposed their kings, built a republic and replaced it with empire.
"Jesus preached humility but under Constantine was used to christen an autocracy.
"The history of struggle is one of repetition, with radicals bought off, killed off or brain washed into submission.
"John Prescott used to be a union man; Gordon Brown used to be socialist.
"Politics can be like a gerbil cage. You go up and up and up to the top slot but with compromises to get their you crash back like the fallen radicals.
"Green politics cannot fail - we have a world to save. If we win power but at the cost of our ideals, that really would be a catastrophe."