Labour MPs and Conservative backbenchers have attacked the government's plans for electoral reform.
Winding up the debate on the Parliamentary Voting and Constituencies Bill on 6 September 2010, shadow Welsh Secretary Peter Hain called the proposals "blatant gerrymandering".
He said Labour wanted to see the bill "decoupled" so that one bill represented changes to the voting system and the other dealt with changes to constituencies.
Mark Harper, the Cabinet Office minister, said the government were "treating voters with respect" in giving them the ability to vote in elections to Scottish, Welsh and Northern Ireland institutions - and in a referendum - on same day.
He added that the bill would create seats of equal size and give people a chance on what voting system they preferred.
He said: "As democrats we should have nothing to fear from letting the people decide."
The bill paves the way for a referendum on changing the Westminster electoral system from first-past-the-post to the Alternative Vote (AV) system, whereby voters rank candidates in order of preference on the ballot paper.
It also proposes cutting the number of MPs by 50 to 600, and redrawing parliamentary boundaries.
During the debate, Tory MP Daniel Kawczynski who is chairman of the All-Party Parliamentary Group for the Promotion of First Past the Post, said that the referendum was a waste of time.
"I think it's the equivalent of watching Nero fiddle while Rome burns," he said.
"We have so many problems in our country yet we are being distracted by this ridiculous referendum which is going to cost taxpayers between £80m and £100m."
Conservative Eleanor Laing criticised the Liberal Democrats for insisting on the AV referendum as part of the coalition deal.
Ms Laing said she would support the bill because it was a "matter of honour" to fulfil the agreement.
A Labour amendment, which would have stopped all further progress of the bill, was defeated by 347 votes to 254.
The bill passed its second reading, by 328 votes to 269.
Watch the first part of the debate