"no taxation without representation". Or should that be: "no representation without taxation"? The pledge by the Tories, Liberals and Labour to give Holyrood greater tax-raising powers if there is a No vote in September has reinvigorated a decades-old debate.
High-profile Conservatives such as one-time leadership contender John Redwood argue there is now an urgent need to find an answer to that most knotty of political problems, the West Lothian Question.
English taxpayers will not countenance Scots MPs voting on taxes they themselves would not have to pay, he warns. The heat around the issue could intensify if there is a No vote and Labour, with many Scottish and Welsh MPs, wins next year's general election by a narrow margin.
But increased pressure alone will not find a solution to the issue. For while Tories calling for a system of "English votes for English laws" say Labour opposition is based on self-interest, a charge Labour throws back at them, the truth is there are plenty of bear traps for all political parties.
So far the SNP are the only party that thinks it has a clear cut solution - independence. Unsurprisingly, this has failed to win over pro-Union politicians.
Some hope lay with the McKay Commission, set up by the Coalition a few years ago to look into the issue but its recommendations appeared to please no-one.
Labour's concerns over "English votes" include the risk of unintended consequences. Some fear an English Parliament sitting within Westminster could ultimately lead to a federalist UK, a policy only the LibDems back.
There are also concerns among some that designating more and more legislation English, Scottish, Welsh or Northern Irish-only would drive a wedge between the parts of the UK, leading ultimately to Scottish independence.
The biggest fear is the size of England would mean other parts of the UK could not help but feel the effect of its decisions, without having any say and with their politicians "second class" MPs.
Research by Labour MP Tom Greatrex highlights how little legislation at the moment is genuinely England-only. Also, what of the potential effects on politicians and political parties themselves, with all that could mean for voters?
Would Scottish and Welsh MPs be able to run Westminster departments that deal in large part, but not exclusively, with English issues?
If politicians from smaller parts of the UK found themselves, by consequence, effectively barred from the top job of party leader or Prime Minister, would the parties fracture?
In a speech on the issue on Tuesday night Mr Redwood even suggested an English First Minister might be needed.
The thought of a large, separate power base within the Commons is intriguing just days after the Tory mayor of London announced his plans to return to Westminster. Boris for English Prime Minister anyone? Any future commission on the issue will have its work cut out.