Ignoring election watchdogs' expert advice would taint a Scottish independence referendum, the Commons has been told.
MPs urged Holyrood to accept recommendations from the Electoral Commission about how to phrase a question offering Scots to split from the UK.
The Scottish Government plans to ask voters: "Do you agree that Scotland should be an independent country?"
The commission is scrutinising the draft question, but the Scottish National Party (SNP) is not bound by its recommendations.
Conservative Bob Blackman, MP for Harrow East, said: "Clearly it's important all parties respect the independence of the Electoral Commission. If the SNP administration were to ignore the advice of the Electoral Commission, it would taint the whole question of the process and call into question whether a referendum was fair."
Labour's Ian Davidson, who chairs the Scottish Affairs Select Committee, said while the Electoral Commission could be "a trifle wishy-washy on occasions, it is necessary to have an actual body deciding these important questions".
Speaking at Scottish questions in the Commons, he added: "The alternative is to have separatists as both referee and player in these circumstances. It is simply unacceptable to have a side which is on one side of the argument also deciding the rules."
Scottish Secretary Michael Moore hailed the "highly-respected" and "trusted" commission's "expertise and experience". He said the referendum, due in 2014, needed to be seen to be fair, with no opportunity for critics to query the result.
"I don't think it would be in the interests of the Scottish Government or any nationalists to put themselves against the advice of the Electoral Commission when that comes forward," he said. "I am ready to stand by the advice its gives, I hope the Scottish Government is too."
The SNP's Mike Weir accused the UK Government of rejecting the commission's advice over council tax referendums, though Mr Moore pointed out no such referendums had been held.