Covering the rammies and stooshies of the Scottish referendum build-up, I find myself more and more trying to shoehorn in the popular, if hackneyed, Robert Burns line: “The best-laid schemes o' mice an' men/Gang aft agley”.

I hadn’t brought myself to quote it yet, but today’s most recent No campaign stumble has brought me closer.

This morning, the three main party leaders released a joint declaration promising more power to Scotland in the event of a No vote.

It was illustrated on the Daily Record’s front page as a faux-yellowing piece of parchment with the headline: “The Vow”.

Well, it seems to be yellowing rather quicker than perhaps even the Record’s photo editor would have expected.

The leaders’ last-minute deal for Scots, in the hope of staving off a Yes vote on Thursday, has caused outrage among MPs.

The Evening Standard has done some reporting on politicians’ furious reactions to their party leadership’s apparently “panicky 11th-hour promises”, which is how I analysed this move this morning.

Some Tory MPs in particular are astonished that David Cameron has been so willing to further what they already saw as “unbalanced devolution”. They view the proposed new package as “unfair”, as it keeps in place the Barnett formula, a distribution of public spending that gives Scots around £1,400 more per person than the rest of the UK. There are also plans underway for Holyrood to have greater tax powers, the details of which the parties have yet to decide.

The Standard quotes two Tory MPs concerned at the PM apparently in danger of devo-maxing out the UK taxpayer:

Mark Field, the MP for the Cities of London and Westminster, said: “My constituents will be aghast if the unbalanced devolution from 1979 is made even worse.”

Tory MP Peter Bone added: “I don’t see why people in the East Midlands should be worse off to the tune of thousands of pounds than the people of Scotland.”

The Telegraph reports a female Tory MP calling Cameron's act "desperate": “There will be a bloodbath. Last night as I was listening to Cameron saying we are going to be providing all these additional benefits to Scotland, when we are struggling in so many areas of the UK. . . It’s all happening on the hoof, in cliquey conversations on telephones in Downing Street. It isn’t happening, and there are a number of us who are incensed who will make sure it isn’t going to happen. But let’s see what the results are first.”

The Standard's piece also hints that there will be plenty more open criticism of Cameron’s leadership on this following the referendum on Thursday. Labour MPs are also apparently disgruntled about how their party has neglected to canvass voters effectively in Scotland.

All this paints a very fraught future few months for British politics in the case of a No vote. Unlike the personal political impact of a simple, brutal Yes vote – after which it is most likely Cameron and maybe even Ed Miliband would have to resign – the No vote is not as simple.

If Scotland stays, there will be pressure on the pro-Union party leaders to thrash out and rush through their power pledges. However, Tory backbenchers opposing this speed and direction of change will be tugging at Cameron from the other side.

This could have two effects. The first would be for Cameron to be presiding over an even more divided party in the build-up to 2015, helping Ed Miliband – and his party’s rather well-timed “people-powered public services” devolution agenda – gain more popularity and credibility. The second effect could be the leaders flagging and forgetting the current pre-referendum momentum in the less life-and-death atmosphere of a No vote aftermath. As William Hague commented last week, the power pledge is “not a statement of government policy” and is more akin to statements made by party leaders in election campaigns.

What was it that Burns wrote? “The best-laid continuation of the Barnett allocation for resources o' mice an' men gang aft agley”.