Sailesh Patel, external: I'm looking forward to the #bbcindyref - love political debates and Salmond and Darling should a lively debate.

Iain MacLaren, external: But seriously #BBCindyref the debate is not between these two guys its about two possible futures. not parties.

The Sunday Herald's Paul Hutcheon, external: I understand the FM won't be mentioning aliens tonight #bbcindyref

Polling expert Prof John Curtice of Strathclyde University told the BBC news channel the "Yes" campaign made some progress in the polls over the winter.

He said: "On average the Yes side, once you take out the don't knows, increased from around the 39% mark to around the 43% mark."

"But since then, frankly, very little has changed. If you take the average of the last half dozen polls that have been conducted, it is still 43% for 'Yes' and 57% for 'No'.

"Given what happened three weeks ago with the first leaders' debate, that to some degree comes as something of a relief to the 'Yes' side because it was felt that Mr Salmond lost that debate and the first opinion poll after that debate suggested 'Yes' had gone down.

"Of course, don't believe one opinion poll. Three subsequent opinion polls suggested, if anything, maybe 'Yes' support had gone up a little bit."

Jackson Carlaw MSP, external: Will Salmond have learned to answer questions directly following the 1st #ScotDecides debate? A nearly thirty year political career says no.

Head of Sport for Yes Michael Stewart, external: Don't allow NO to con us into allowing them to squander the next 40 years of OIL. The industry is booming #indyref

Louise Sayers
BBC Scotland

What do our voters in Aberdeen hope to get out of tonight's debate?

David Braunholtz, left, is undecided. He said: "I would like to hear more information about what maximum devolution might come about in the event of a No vote."

Stuart Bowler, centre, is voting "No". He said: "I hope Alistair Darling doesn't get bogged down in data. I want to know what the real benefits would be of staying in the union."

Gillian Martin, right, is voting "Yes". She said: "I want to hear a debate that isn't just about currency and the EU. The message is more important to me than performance. Boxing match-style debates are quite annoying."

You can give us your thoughts now, or once the debate has started, on Twitter using #BBCindyref, by texting 61124 or by emailing Talkingpoint@bbc.co.uk.

First Minister Alex Salmond has also arrived at the venue.

Image source, Getty Images

Ed Thomas
North of England Correspondent, BBC News

Diana Wallis is a former MEP for Yorkshire and the Humber who supports more powers for the English regions.

Ahead of tonight's debate, she told the BBC: "If Scotland can have something and they have the same population as us, Wales has something, what about Yorkshire, why can't we have something? I think we are underpowered."

TELEVISION: It all starts at 20:30 and runs until 22:00. Viewers in Scotland can watch the broadcast on BBC One Scotland, while viewers in England, Wales and Northern Ireland can watch on BBC Two.

The debate will also be shown on the BBC News Channel and BBC World News. If you miss it live, you can tune-in to BBC One between midnight and 01:30 to watch again. And of course the programme will be available on the BBC iPlayer.

The chairman of the Better Together campaign, Alistair Darling, has arrived at Kelvingrove Art Gallery and Museum.

Image source, Getty Images

This latest poll of voters puts the "No" side ahead.

Professor John Curtice has called tonight's debate an "invaluable second chance for Alex Salmond".

Journalist Alex Massie said the problem Alex Salmond has is that "the case for independence is on trial and he has to satisfy beyond reasonable doubt that the case is robust enough to make it a worthwhile venture.

"Alistair Darling has a much easier task. He just needs to hug Alex Salmond close. If you think of it in terms of a football match, a dull scoreless draw will suit Alistair Darling fine this evening.

"Kill the clock, kill time, prevent anything happening, park the bus to avoid giving Alex Salmond the opportunity to have a good evening and the momentum he would get as a result of that.

"Alex Salmond needs a clear-cut victory if this debate is to change anything."

As the minutes tick down to the debate, the BBC's Gavin Esler was talking to journalist Ruth Wishart, who is in favour of independence and Alex Massie, who wants to keep the union.

Ruth Wishart said she expected Alistair Darling to pounce on the currency issue once again.

She said a favourable line of attack for Mr Salmond would be to continue his assertion that the NHS in Scotland is under threat, linking this from the fact that the NHS in England has taken a significantly different route.

The NHS is quite a good issue for female voters, Ruth Wishart said. And the Yes campaign has found women harder to attract.

BBC political reporter Andrew Black, external: Spin room filling up ahead of Salmond v Darling showdown. Main man Prof John Curtice here to keep us right #indyref

Image source, Andrew Black

Louise Sayers
BBC Scotland

Robyn Shepherd - who will be voting "No" - hopes tonight's debate will be an improvement on the first one, which she describes as "car crash television".

Howard Kennedy will vote "Yes", and he believes the biggest surprise at the last debate was Alex Salmond's tone.

He said: "He's normally quite robust but for this he took a step back."

How will tonight's debate work? The broadcast will be split up into four sections.

SECTION ONE: Opening statements - Alex Salmond will go first, Alistair Darling second.

SECTION TWO: The issues- the two men will debate four topics titled;

1.Economy

2.Scotland at home

3.Scotland in the world

4.What happens after the vote?

Each will be introduced with a question from the audience.

SECTION THREE: Cross-examination - Alistair Darling will go first, Alex Salmond second.

SECTION FOUR: Closing statements - Alex Salmond will go first, Alistair Darling second.

Louise Sayers
BBC Scotland

Before last month's STV debate the BBC gathered a group of undecided voters together in Fife to watch the debate.

For tonight's debate we're in Aberdeen to get reaction from nine voters - three voting "Yes", three "No" and three who are still undecided.

We'll be bringing your their thoughts on the debate throughout the night.

With the first of the postal votes about to be sent out and only a little over three weeks until the independence referendum, this looks like it will be the last head-to-head debate between the two figureheads.

It will be screened on BBC One in Scotland.

Across the rest of the UK it will be on BBC Two, from 20:30 BST.

There's not long to go until Scotland votes in the referendum...

It is the second time the two men have met face-to-face for a television referendum debate. The first was on STV on 5 August.

Steven Brocklehurst
BBC Scotland news website

Welcome to the BBC's live text coverage of the Scottish independence debate between Alex Salmond and Alistair Darling.

Scotland's First Minister and the leader of the Better Together campaign will be going head-to-head in an hour's time.