SINCE the referendum the SNP has been calling all the shots and the Yes campaign has maintained the initiative in the continuing arguments, according to the former civil servant who was in charge of the Scotland Office this time last year.

Alun Evans told the British Academy in his inaugural lecture as chief executive that it was time to make a “big, bold and generous offer to Scotland” to stop Westminster continually playing “catch up” with the SNP, which had “not worked and probably will not work”.

“That offer needs to be – whatever people choose to call it – full fiscal autonomy, devo max plus or, in the language of Gladstone: Home Rule for Scotland within the United Kingdom,” he said.

Evans summarised the offer as full devolution of tax-and-spend to the Scottish Parliament and Government, except for reserved areas; full responsibility for domestic policy and spending, along with energy policy and onshore and offshore activity; and agreement on certain shared responsibilities within the UK. He said these would all be set within the framework of the continuance of the UK as a constitutional monarchy.

He also envisaged a shared economic area with monetary policy set by the UK central bank’s monetary policy committee on which Scotland’s views should be represented and defence and overall conduct of foreign policy run by the UK.

But he said the arrangement had economic, political and constitutional conditions.

He said: “First, the economic condition. This arrangement would, by definition, spell the end of the Barnett formula as it applied Scotland. There would need to be new and a more modern formula to apply to Wales and Northern Ireland. And Scotland would make a payment to the UK Government for UK-wide service and provision.”

On the political conditions, Evans said while there was no answer to the West Lothian question in its purest sense, he would reduce the number of Scottish MPs at Westminster.

Evans went on: “Third, the constitutional condition. This issue has to be put to bed for a generation, not for a year or for five years.”

However, the SNP dismissed Evans’s idea of a conditional offer. MSP Mark McDonald said: “It’s time for the Westminster parties to finally deliver the extensive powers we were promised last year.”