Theresa May will vow never to allow the UK to become "looser and weaker'' in a speech ahead of a meeting in Scotland with Nicola Sturgeon.
Lamont Defends Better Together Move
Labour's decision to campaign jointly with the Conservatives in the independence debate was "the right thing to do'', Johann Lamont has insisted.
The Scottish Labour leader said at one point questions had been asked about whether her party should work together with the Tories in the Better Together campaign group.
But she said she was "absolutely clear'' taking part in the cross-party campaign had been the correct decision.
Ms Lamont, speaking in a BBC One Scotland documentary How the Campaign was Won, said that working together with the other pro-union parties "feels like it was a logical and sensible thing to do''.
She said: "When I first got elected as leader that was very much the question - would you campaign with other parties? Particularly, would you campaign with the Tories? And it was the right thing to do. I'm absolutely clear now it was the right thing to do.''
Tory leader Ruth Davidson said the decision by her party, Labour and the Liberal Democrats to all take part in Better Together had been key in the independence campaign.
She told how the launch of Better Together had "caused a stir'' as the leaders of the three parties took to the stage with the campaign's chairman, former chancellor Alistair Darling.
Ms Davidson told the programme: "I think what caused a stir was the very first picture that was released from the launch.
"It was Alistair Darling and the three party leaders. Nobody had really seen people coming together before and I got lots of emails from people saying it's great to finally see politicians coming to work together on something.
"I think a lot of people thought that that could never hold, that Better Together would have so many internal tensions that it would fall apart, and it never did.''
Better Together campaign director Blair McDougall conceded the First Minister had "had a better night'' than Mr Darling in the second television debate between the two men.
But he told the programme: "I think over the course of those two debates if someone had said that, you know, you'd get a score draw over the course of those two debates, we'd have taken that.
"As the people who were holding onto a lead at that point, we were pretty comfortable across the two debates.''
Scottish Green co-convener Patrick Harvie explained his party's decision to join the pro-independence Yes Scotland campaign, saying there was a "clear majority'' of members in favour of this at their conference.
He said: "People were keen to be a pro-active voice both alongside colleagues under the Yes Scotland banner and with our own distinctive name and brand and putting across a distinctive Green Yes set of reasons, set of arguments why Scotland would be a greener and fairer country, if we voted for independence.''
Yes Scotland chief executive Blair Jenkins said they had talked about their organisation "as a movement not as a campaign'', telling the programme they had done that "because we knew that in order to win, we genuinely had to become a national movement that was much bigger than party politics, much bigger than politicians''.
A Scottish boxer has died in Thailand of suspected heatstroke.
Scotland outperformed the rest of the UK last year with an annual increase of more than 15% in visitors to its attractions, new figures show.
The population of an iconic bird of prey is poised to soar after a scheme to boost golden eagle numbers attracted £1.3 million in funding.
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