The first talks aimed at securing a new deal on more powers for Holyrood were "constructive" with "important principles" agreed between all parties, the chairman has said.

Lord Smith of Kelvin said those involved in the discussions in Edinburgh had "committed to work together to achieve a positive outcome".

All five parties represented at Holyrood were involved as the Smith Commission - set up by the UK Government after last month's independence referendum - held its first full meeting.

In the run-up to the independence ballot, David Cameron, Ed Miliband and Nick Clegg all vowed that substantial new powers would be transferred to Scotland if the country voted to stay part of the UK.

The promise of more devolution to Scotland has sparked calls from some quarters for only English MPs to be allowed to vote on legislation which impacts just England.

But as part of the principles underpinning the work of the Smith Commission, it was agreed that further devolution for Scotland should "not be conditional on the conclusion of other political negotiations elsewhere in the UK".

The aim of the Commission is to draw up a "substantial and cohesive package of powers" in a bid to bring about a "durable but responsive democratic constitutional settlement which maintains Scotland's place in the UK and enhances mutual co-operation and partnership working".

After today's talks, Lord Smith - who recently chaired the Organising Committee for the Glasgow 2014 Commonwealth Games - said: "I was pleased with our meeting today. We have good people round the table, each with their own deeply held views, who have committed to work together to achieve a positive outcome to this process.

"We had a constructive discussion and agreed some important principles, which will guide us towards an agreement on a package of substantial and cohesive new powers to strengthen the Scottish Parliament within the UK."

Under the timetable already agreed for reform, an agreement on recommendations for what new powers should be transferred north has to be reached by the end of November, with draft legislation produced by the end of January 2015.

This will then be implemented by whatever party wins next year's general election.

"I think we will meet the deadline," Lord Smith said, adding that a "good start" had been made towards securing a deal, but there was still "a long way to go".

He said the talks, which involved representatives from the SNP, Labour, the Conservatives, Liberal Democrats and the Scottish Green Party, had been "actually very good natured", with the principles agreed for the detailed negotiations which will take place over the coming weeks.

"We agreed all the guiding principles that are going to form our talks over the next several weeks," Lord Smith said.

"We went round the table and tried to find common ground on all the issues, and then we concentrated on constitutional issues and we reached quite an area of common ground there.

"So, all in all, a good start but a long way to go.

"I can't break it up like a cake and give you percentages (of common ground), but the issue that I can say that we went into in some detail, the constitutional issues - a very broad agreement."

He stressed: "I'm very clear that the remit that I have been given is to look at the Scottish issues, Scottish votes if you like, Holyrood and what powers ought to be devolved to Holyrood.

"That's what I have been concentrating on and that's what I will deliver on."

The focus of today's talks was on the different proposals all five parties have made for further devolution, which have seen the two pro-independence parties put forward the most far-reaching suggestions, with the SNP calling for full responsibility for all taxes to be transferred to Scotland and for Holyrood to be given responsibility for all domestic spending, including welfare.

Meanwhile Labour's proposals would see the Scottish Parliament made responsible for raising around 40% of its budget, and would also see the devolution of some elements of welfare policy, including housing benefit and attendance allowance.

While Labour have claimed falling oil revenues mean there would be a £5 billion "black hole" in the nationalists' plans Lord Smith said: "I didn't hear that referred to in today's talks.

"We're going to get a lot of that sort of noise outside this meeting, but I can tell you all the parties that were here today were all conducting this in a real friendly spirit. So I am really quite encouraged."

Practical guidelines for the discussions were also agreed by those involved, with these making clear that the parties involved would "make no substantive comment on the talks until they are concluded and the final report has been published".

Scottish Labour leader Johann Lamont MSP said afterwards that the talks were "yet another important step forward in the process of delivering real change to the Scottish Parliament while maintaining Scotland's fair and equal voice in the UK".

Ms Lamont added: "On September 18 the people of Scotland voted to remain part of the United Kingdom and it is vital that in the following weeks we all work constructively to strengthen devolution and deliver positive change.

"We believe in powers for a purpose, not just at Westminster and Holyrood, but for local authorities and local communities. The Commission cannot become a hostage to the highest bidder, nor to powers for powers' sake. We cannot end up with a settlement that will see the people of Scotland worse off.

"That is why Labour is committed to bold change, radical change, but change within the UK. A strong Scottish Parliament backed by the United Kingdom. That is the sovereign will of the people of Scotland and we aim to honour that."

The SNP said full fiscal autonomy remains an option for Scotland after the Prime Minister said he would stand by promises made in the run-up to the referendum at Prime Minister's Questions today.

Angus MacNeil MP said: "David Cameron said just days before the referendum that if Scotland stays within the UK then all options of devolution are there and they are possible. Today he confirmed that he stands by his promises.

"Cameron's comments, of course, mean that full fiscal autonomy is on the table, which includes devolving full control of Scottish taxes and spending to the Scottish Parliament.

"A new poll shows superb trust ratings for the SNP and Nicola Sturgeon on more powers - as Labour's woes in Scotland continue, with only 1% of people trusting Ed Miliband most to deliver extensive new powers.

"Our key focus is on delivering powers for a purpose - that means proposals that will deliver real change for the people of Scotland and better equip the Scottish Parliament to create jobs, protect public services and tackle inequality."