Changing the constitution so that only English MPs could vote on laws affecting solely England would lead to the "fracturing" of the United Kingdom, Ed Balls has warned.
Speaking at a event hosted by The Huffington Post at the Labour Party conference on Monday evening, the shadow chancellor said a so-called 'English votes for English laws' rule would "undermine" the union.
Asked how he would describe the current system in parliament, where Scottish MPs can vote on many domestic English issues while English MPs can not vote on the same domestic Scottish issues, Balls said it was "a union of our United Kingdom that has worked very well". He added: "I don't want to throw out the baby with the bathwater."
"This idea you can simply say, in a David Cameron-Farage like way, you know, we've got to sort out this situation where we stop anybody but English MPs voting on English laws, if you say we are going to do that because anything else is unfair, the consequences of that is the fracturing of the union," he said.
"It leads you immediately into two parliaments or two prime ministers or two classes of MPs. There is no way the union would survive that."
Balls said he wanted the system of governance across the UK to be fairer to English cities and county regions but he did not want it to be "narrowed down" to that one issue rather than "proper long-term constitutional reform". The shadow chancellor also accused the prime minister of engaging in "immature, puerile, schoolboy politics".
Following the No vote in the Scottish referendum last week, Cameron said any devolution of more powers to Scotland should be matched by a fairer deal for England.
For years Tory MPs, and others, have felt it unfair that Scottish MPs, most of whom are Labour, are able to vote on laws that only affect England. Labour have accused the prime minister of exploiting the result of the referendum for partisan gain.
William Hague has held out the prospect of talks with Labour on reform of the way MPs at Westminster vote in the wake of the referendum result. The Leader of the Commons and former foreign secretary said that ministers were ready to open discussions with the other parties on the issue of 'English votes for English laws'.
Earlier today Ben Bradshaw, the former Labour culture secretary, told The Daily Telegraph that the party needed to tackle the "unfairness" of Scottish MPs voting on English laws. He said it was time the party acknowledged the "imbalance" in the system and made it clear it was "fighting for England".