Image copyright Various Image caption Conservative leader David Cameron, Labour leader Ed Miliband and Lib Dem leader Nick Clegg have signed a pledge to devolve more powers in the event of a No vote in the referendum

Both sides in the Scottish independence referendum debate have seized on a pledge by the three main Westminster parties to devolve more powers.

The pledge, signed by David Cameron, Ed Miliband and Nick Clegg, also promises equitable sharing of resources and preserving the Barnett funding formula.

The "Yes" campaign described it as an "insult" to voters and asked why it had taken so long to offer.

Better Together said it was "a vision around which Scotland can unite".

In other developments:

The pledge signed by the Conservative, Labour and Lib Dem leaders appears on the front of the Daily Record newspaper.

The first part of the agreement promises "extensive new powers" for the Scottish Parliament "delivered by the process and to the timetable agreed" by the three parties.

The second says the leaders agree that "the UK exists to ensure opportunity and security for all by sharing our resources equitably".

Image copyright Daily Record Image caption The pledge was carried on the front page of Tuesday's Daily Record newspaper

The third "categorically states" that the final say on funding for the NHS will lie with the Scottish government "because of the continuation of the Barnett allocation for resources, and the powers of the Scottish Parliament to raise revenue".

The Barnett formula is the method used to determine the distribution of public spending around the UK.

However, in an interview with BBC Radio 4's World Tonight programme, Lord Barnett, who set up the system in 1978 when he was chief secretary to the Treasury, said it was "grossly unfair" and repeated his call for it be scrapped.

First Minister Alex Salmond told the BBC's David Dimbleby the plans for more powers for the Scottish Parliament were: "Nothing like home rule, it's nothing like Devo Max, it's not even Devo-plus.

"It is actually an insult to the intelligence of the people of Scotland.

"To re-hash these proposals last gasp in the campaign and hope beyond hope that people'll think it's anything substantial. It is not."

Shadow Foreign Secretary Douglas Alexander, speaking for Better Together, denied the powers pledge had come too late in the referendum debate.

Penultimate day

He said: "Here in Scotland, we have been talking about these powers for many months. What we are saying today is we can have the best of both worlds. We can have a stronger Scottish parliament but with the strength, stability and security of the United Kingdom.

"That pledge, that vow that we can have faster, safer, better change is actually a vision around which Scotland can unite."

Media playback is unsupported on your device Media caption Douglas Alexander says the pledge represents "the best of both worlds"

He added: "I don't think there's any embarrassment about placing policies on the front page of papers with just days to go. I think the 'Yes' campaign are struggling.

"The economic risks suddenly became very real last week, and at the same time we are offering what I believe most of us here in Scotland want, which is faster, safer and better change."

Mr Alexander dismissed "Yes" campaign claims that independence is the only way to get the government Scotland votes for.

The pledges were first outlined by the former prime minister, Gordon Brown, and endorsed by the three main unionist parties in Scotland.

Power play

Brian Taylor, BBC Scotland Political Editor

Perhaps it might help if we took a little look at the pledge of more powers set out by the pro Union parties today.

The one that was trailed last night by Gordon Brown and covered on the telly and the wireless.

Firstly, it would appear to confirm the prime minister's acknowledgement that any notion of deferring the issue of more powers - conceptually if not yet in agreed detail - has been abandoned.

No more talk of settling the question of independence then turning to more powers. The pro-Union parties have seemingly concluded that they must be more upfront, now, about their plans.

Read Brian's full blog here.

On the penultimate day of campaigning ahead of Thursday's referendum, the "Yes" side was focusing on jobs and the NHS, while the "No" side promised change and a "better Britain".

Deputy First Minister Nicola Sturgeon and Finance Secretary John Swinney met apprentices at an engineering firm in Renfrew where they argued that independence would allow Scotland's economy to grow, creating jobs and opportunities.

Image copyright PA

Image copyright PA Image caption Apprentice Craig McKee manufacturing a steel "Yes" sign at Steel Engineering in Renfrew

Image copyright EPA Image caption "Better Together" supporters at a rally in Glasgow on Tuesday

Ms Sturgeon said: "In just two days' time, polling stations will open and voters across the country will hold Scotland's future in their hands. Independence is our opportunity to build a better future - creating jobs and protecting our NHS.

"Only a 'Yes' vote will ensure we have full powers over job creation - enabling us to create more and better jobs across the country. So instead of almost 40,000 young people leaving Scotland each year as is currently the case, there will be more opportunities for our young people here at home.

"As part of the UK, our NHS budget faces knock-on impacts of the privatisation, cuts and charging agenda that is ripping the health service south of the border to bits. With a 'Yes' vote we can ensure our NHS is protected for future generations by enshrining it in our written constitution."

Uncertain economics

Robert Peston, BBC Economic editor

Here is the bad news if you haven't made up your mind whether to vote for Scotland to become independent - economic analysis cannot give you the answer.

That is partly because this dismal science is not capable of giving wholly (and sometimes even partly) accurate forecasts about the future prosperity of nations.

Look at the case of a comparably sized small country, Ireland. A decade ago many economists (and others) saw it as a rip-roaring success, that had become considerably richer on a per-head basis than the UK.

Then three years ago it looked like a total basket case, as its property sector and banks imploded.

Today it can be seen as a model of how a determined small country can reconstruct its economy in adversity, in stark contrast to the inertia in a bigger country such as Italy.

Read more from Robert Peston's blog here.

Speaking at a Better Together campaign event in Clydebank, West Dunbartonshire, former Labour Prime Minister Gordon Brown accused the SNP of "perpetrating a lie" about protecting the NHS with independence.

Mr Brown said: "I think people are going to come to the conclusion that the change they really want is to have a Scottish Parliament as part of the UK, not the change that the SNP want, which is the chaos of a separate state.

"The NHS lie of the Scottish National Party has been exposed.

Media playback is unsupported on your device Media caption Ed Miliband was caught in a media scrum during a visit to a shopping centre, explains the BBC Norman Smith

"The Scottish Parliament can keep the NHS in public hands with its existing powers."

He added: "If the SNP continue to say they are powerless to protect the NHS in Scotland, let them make way for a Labour government in Scotland and we will protect the NHS."

Meanwhile, the BBC's Norman Smith said: "There have been chaotic scenes in Edinburgh city centre as the Labour leader Ed Miliband attempted to do a walkabout amongst shoppers.

"Mr Miliband was surrounded by a melee of pro and anti independence supporters as he tried to walk through the St James' shopping centre in Edinburgh.

"Planned interviews with the media had to be abandoned amidst the scrum. Mr Miliband played down the scenes as he struggled to meet any voters. He eventually had to be escorted out of a rear exit."