Opponents on either side of Scotland's independence debate have clashed on the anniversary of the referendum.
The Prime Minister has said last September's result should be respected by everyone.
But Scotland's First Minister Nicola Sturgeon has told David Cameron he is "living on borrowed time" in the eyes of Scots for failing to deliver on pre-referendum promises of more devolved powers.
On 18 September, 2014, Scots voted to stay in the United Kingdom by 55.3% to 44.7%.
In the year since, however, the debate over Scotland's future has remained intense, with support for independence showing a small but steady increase in the opinion polls.
Ms Sturgeon has said she will set out the SNP's position on a second referendum in her party's manifesto for next May's Scottish Parliament elections.
In a speech, she pointed to current Government policies as a possible trigger.
She said: "Right now, what (the Scottish) people see at Westminster is a Tory government failing to fully deliver on the vow it made on more powers for our parliament.
"They see a Tory government continuing to impose austerity on working people and the disabled - way beyond anything required to reduce the deficit and in spite of Scotland electing 56 anti-austerity MPs.
"And they see a government arrogantly pressing ahead with plans to renew Trident - at a cost of £100bn (€136.5bn) - before the House of Commons has even voted and while our public services suffer the pain of their cuts.
"So my message to David Cameron is ... what happens to support for independence in the months and years to come will depend as much on what you do as it will on what we do.
"And right now, you are living on borrowed time."
The Scotland Bill, currently going through the Westminster Parliament, contains pledges to increase devolved powers to Holyrood in areas such as taxation, welfare and VAT revenues.
The SNP says Scotland could be left worse off when all the calculations are taken into account, although that has been rubbished by their opponents.
Speaking ahead of the referendum anniversary, Mr Cameron said: "It's worth remembering that a year ago Scotland voted overwhelmingly to remain part of the UK.
"More people voted to stay together than have ever voted for any political party in Scotland.
"But they didn't just vote to stay together, they voted for a powerhouse parliament, and devolution is now woven into the fabric of our constitution.
"We all signed the Edinburgh Agreement, which was to respect the outcome of the referendum and I think now that's what everyone should do."
