Scotland's First Minister Alex Salmond has said he hopes to get the format for an independence referendum settled with the UK Government within the next few weeks.
Mr Salmond was speaking after a brief discussion on the referendum with Prime Minister David Cameron in 10 Downing Street. Formal talks between the two leaders are due to take place next month, when it is hoped they can settle vexed issues, such as whether there should be one or two questions on the ballot paper.
Orders paving the way for a poll will be tabled in the UK and Scottish parliaments by October 22.
Number 10 described the discussion, on the margins of a regular Joint Ministerial Committee meeting of leaders from the UK's devolved administrations, as a "constructive" stock-take ahead of next month's talks.
Mr Salmond said it was characterised by "goodwill" on the referendum issue from both sides, though he warned that "noises off" - such as a speech in Glasgow by Iain Duncan Smith - could knock discussions off course.
The First Minister was clearly annoyed by the Work and Pensions Secretary's claim that an independent Scotland would be unable to meet its welfare bill without raising taxes or cutting services.
"There was goodwill within the meeting, but of course it is possible that noises from outside - like Iain Duncan Smith - could still blow things off course," Mr Salmond said.
He added: "Within the negotiations, there was goodwill to having this matter settled in the next few weeks in terms of the format of the referendum and then getting on to the real substance, which is the arguments for an independent Scotland."
A Downing Street spokesman said: "It was a constructive exchange, and the Prime Minister remains committed to and hopeful of reaching agreement to enable a Section 30 Order to be tabled in both parliaments by October 22.
"The Prime Minister looks forward to a further meeting with the First Minister next month."
