Suggestions that Westminster might take "revenge" on Scotland in the event of a No vote in the referendum are very real, according to one of the leading architects of devolution.

Canon Kenyon Wright, who chaired the Scottish Constitutional Convention which laid the groundwork to set up the Scottish Parliament in 1999, has urged people to vote Yes.

The canon said independence is "the only way left open, to give Scotland power over her own affairs that is both complete and secure", describing promises of further powers from the unionist parties as looking "suspiciously like a rather desperate bribe".

Labour, the Liberal Democrats and the Conservatives have all put forward their own proposals for further devolution in the event of a No vote.

Yes campaigners have questioned whether these will be delivered, and have claimed Scotland's budget could be cut in future years.

The retired Episcopalian clergyman said: "I believe the suggestions of revenge against the Scots emanating from Westminster are very real if there was a No vote on September 18.

"There will undoubtedly be cuts to the Barnett Formula, affecting the NHS in Scotland, social security, and that benefits will suffer - we've already had (Chancellor) George Osborne and his 'bedroom tax' - and I envisage devolution being undermined despite promises of more powers. Not that I believe that the devolved parliament will be abolished, but its powers will be diminished.

"Like many, I argued for a second question offering a middle way - which I saw not as devolution but as 'constitutionally secure autonomy within a reformed UK'. That door was slammed shut - but not by Scotland.

"Devolution is no longer enough; it's incomplete and even 'max' leaves key areas unguaranteed. So Messrs Cameron, Miliband and Clegg cannot be surprised if I now see independence as the only way left open, to give Scotland power over her own affairs that is both complete and secure. Their way offers neither."

He added: "The latest 'offer' of more powers from the unionist parties looks suspiciously like a rather desperate bribe - but it is not an answer to Scotland's needs."

The canon was speaking as he signed the independence declaration at Yes Scotland's headquarters in Glasgow, and ahead of an appearance in Edinburgh tomorrow.

He will be part of a panel at the launch of a new book, A Constitution For The Common Good by Dr Elliot Bulmer.