THE LibDems have launched a fresh bid to win cross-party support for proposals to increase Holyrood's powers.

Former party leader Sir Menzies Campbell has been asked to identify a package of possible measures that the main parties could rally behind if Scots reject independence.

His proposals will be outlined in a report in the next few weeks. Announcing the move last night, Scots party leader Willie Rennie said he believed a "consensus for change" was growing.

He added: "I think we can be certain that, subject to the consent of voters at the 2015 election, decentralising reform across Britain is now building such momentum that it will happen."

He said the new report would set out a possible timetable for "lasting, permanent constitutional change after the referendum".

Sir Menzies drew up detailed plans for further devolution in a report a year ago.

The package of measures - dubbed "home rule all round" by the LibDems - would hand control of income tax, inheritance tax, capital gains tax and other levies to Holyrood, ensuring more than half the Scottish government's budget would be raised in Scotland.

However, Sir Menzies will also consider alternative proposed systems such as "devo plus" and "devo more" championed by different think tanks in seeking possible common ground.

Mr Rennie, in a speech to the David Hume Institute, said: "Our idea is for a federal structure to the UK or home rule all round' as Gladstone called it.

"For certain and for sure the Scottish Parliament would get new responsibilities to raise the majority of the money it spends.

"Other parts of the UK would be able to acquire those same tax powers if they want them and the substantial legislative authority that is already held by the Scottish Parliament.

"Accountable, powerful, responsible government with the great back-stop and insurance from being part of the UK." Labour and the Conservatives are planning to unveil plans next month for further devolution, if Scots vote to stay in the UK. However, Labour remain split over proposals first mooted a year ago to hand Holyrood full control over income tax.

SNP MSP Linda Fabiani said: "The real kick-start to constitutional change across these islands will be a Yes vote in Scotland in September."