Britain's political system is riddled with "rotten boroughs" and unfair towards the Conservatives, a Midland MP told the Commons.
Tory John Maples (Stratford-on-Avon) said Scotland, Wales and Northern Ireland were overrepresented in Parliament because they had smaller constituencies than England.
Many of the small constituencies, where votes effectively count for more, were Labour-held, he added.
And he urged Tony Blair to back his calls for fairer boundaries - saying it was a chance to kick some of Labour's most troublesome rebel MPs out of the Commons.
Mr Maples said Commons seats boundaries should not be restricted from crossing county borders and electoral reviews should be carried out more frequently, to ensure each MP serves roughly the same number of people.
Introducing his Parliamentary Constituencies (Equalisation) Bill, he said: "That catchy title was not my first choice, what I wanted to call the Bill was the Rotten Boroughs Bill - because that's what we have."
He said there were 230 seats where the electorate is more than five per cent below the national average.
"Several are in Scotland, many are in Wales, and very few are controlled by the Conservatives, which of course is irrelevant to the purpose of introducing this Bill."
He said Northern Ireland was also over- represented in the Commons.
"The nature of the problem is really quite extraordinary. The smallest seat has 21,169 voters, the largest 107,767 - that's over five times as big.
"The Member who represents the smallest seat got 6,213 to get here. The Member who represents the largest had to get 32,717. That can't be right.
"The average UK electorate is just under 68,500 but 239 seats are more than ten per cent above or below the target. The injustice is self-evident, the cure is obvious and in our own hands."
The Bill received its first reading but stands little chance of becoming law without Government support.