THE Liberal Democrat pledge ahead of September 18 has been laid out by Sir Menzies Campbell - vote No and we will persuade the other parties to cede fresh powers to Holyrood.

The former party leader was strong on arguing why his own party believes in Home Rule and federalism, but less convincing on how they might persuade Labour or the Conservatives to join this vision.

Sir Menzies suggested the ultimatum of an October summit, convened by the LibDems' Scottish Secretary, at which the Tories and Labour would have pre-registered for change of some kind, would be crucial to persuading Scots to vote No.

"As a result of this referendum debate, and the campaign leading up to it, the Scottish public will be well-versed in the options. We want to be able to capture that moment."

But there were tricky moments at the press conference. Under the document's own timeline, Sir Manzies suggested that the Scottish Government "agrees to release civil servants to assist with future work on financial powers after a No vote."

Asked whether there was a parallel view that Whitehall civil servants should be "released to assist with future work on a Yes vote" there was confusion.

It was clarified that none of this would apply until after September.

There was also a phrase about the post-referendum meeting of the three parties. "Its agenda will be set by the result of the referendum," said the report. This was not to be construed as a crude warning about the scale of the vote.

Sir Menzies insisted that the Liberal Democrats, as the original party of Home Rule, could continue to lead in the way they had through the Scottish Constitutional Convention a generation ago.

"The lesson of recent history is that constitutional change is best achieved when it is secured by consensus among political parties," and to that end he backed the Reform Scotland think-tank's notion of a "Glasgow Agreement" where the three pro-Union parties spell out what they are prepared to offer in terms of extending Holyrood powers.

"Equipping Scotland with more powers, what I regard as an early step for a federal UK, can be done.

"2015 is the time when it should be done."

Yes Scotland chief executive Blair Jenkins said: "We have heard warm words before from Westminster politicians about powers for Scotland in return for a No vote. They came to nothing in 1979 and they'd come to nothing again.

"In the absence of being able to give any guarantee at all to Scotland of more powers, Ming Campbell preferred to indulge in silly name-calling."

l The result of the independence referendum will make no difference to the future of the Grangemouth oil refinery, according to its boss, Jim Ratcliffe, whose company Ineos operates the petrochemical plant with 1300 workers.

"It will survive in both scenarios," declared Mr Ratcliffe, adding: "I don't think the Scottish vote will make any difference to Grangemouth one way or the other."