David Cameron reportedly ignored Alistair Darling's plea not to restrict Scottish lawmakers' voting rights in the immediate aftermath of the country's referendum in September.
According to the Guardian newspaper, the Better Together campaign leader phoned Cameron at 0500 GMT on the morning of the referendum, warning him not to restrict Scottish MPs' power to vote on English laws in Westminster.
Darling said that this course of action would conflating the issue of English-only votes with the devolution of further powers to the Scottish parliament, and would risk letting Alex Salmond back in the front door.
The issue of restricting Scottish MPs from voting on English matters in Westminster should be addressed but not in the immediate aftermath of the independence referendum, he added.
Cameron went on to congratulate Darling for "a well-fought campaign", as he promised to deliver on pledges. The PM "made clear to Darling that it was important to achieve a 'fair settlement' for the rest of the UK".
All the mainstream political parties promised that Westminster would grant Scotland enhanced devolution if Scots voted against independence during September's historic referendum.
This has led to some politicians calling for "English votes for English laws". This comes in answer to the West Lothian Question, which asks why MPs from other parts of the UK should be able to vote on certain English issues, when English MPs have no say on those same issues in the devolved national assemblies.
On 18 September 55% of Scots voted against independence while 45% wanted to break the union.
A day later, the UK government appointed the panel, led by Lord Smith, to analyse what extra powers Scotland could be given over taxation and social issues, without creating an imbalanced schism within the union.
Cameron confirmed that English Votes for English Laws would be addressed "in tandem with, and at the same pace as, the settlement for Scotland".
Within weeks the SNP surged in popularity and racked up thousands of new members.