Gordon Brown has called for 100,000 Scots to sign a petition demanding that Westminster keeps its vow on further powers for the Scottish Parliament.

Mr Brown has also outlined a "14-point practical plan for new powers", which include more control over investment, job creation, welfare, transport, elections and taxation.

He has called for the transfer of up to £4 billion of VAT revenues to the Scottish Parliament alongside devolving the majority but not all of income tax.

This would avoid falling into what he described as "the Tory trap that would end income tax as a shared tax and threaten to reduce the rights of Scottish representatives at Westminster on budget tax decisions".

The former prime minister was instrumental in establishing a timetable for more devolution and in the signing of "the vow" by David Cameron, Nick Clegg and Ed Miliband, just days before Scotland voted to reject independence in the referendum.

The vow pledged swift "extensive new powers" for Scotland under a No vote but the Prime Minister's post-referendum plans to restrict Scottish MPs from voting on English matters led to fears that their delivery will be stalled.

Downing Street has said that the Scottish devolution pledge does not depend on giving more powers to English MPs at the same time.

If English votes for English laws were brought forward, Labour would see its power diminished at Westminster due to its much higher number of Scottish MPs.

Mr Brown plans to present what he hopes will be a 100,000 strong petition demanding there should be no strings attached to the original vow to the House of Commons on October 16.

In a letter sent today to his constituency party, Mr Brown also outlined a plan to move devolution forward quickly around areas of agreement so that "the Scottish Parliament can get down to work improving job opportunities, our schools, our social care, our Scottish NHS and our environment".

He called for 14 new powers to be devolved to Scotland, covering borrowing, welfare, the Crown Estate, employment rights, health and safety, equality, income tax and an assignment of a share of VAT revenues, among other areas.

Mr Brown wrote: "The vow made by three party leaders on September 16 was a self-standing set of promises to the people of Scotland.

"Yet immediately after the referendum result, a new proposal that was never raised in the pre referendum discussions and yet being material to the referendum should have been raised before the vote was introduced - to lower the status of Scottish MPs in the UK when voting on matters including tax.

"I agree with the chairman of the previous Conservative review Kenneth Clarke that care has to be taken to get the precise changes right, and at this point we need to understand that whatever the disagreements now over the status of Scottish MPs, the pre-referendum vow signed by each of the pro-devolution parties' leaders contained no ifs, no buts and had no conditional clauses and no strings attached and it was not presented as part of wider proposals yet to be unveiled, but as stand-alone and self-contained."

He added: "The Tory trap that we are in danger of falling into is to devolve all decisions on Scotland's income tax rates away from Westminster and then to deny Scotland representation in votes on budget decisions on income tax rates.

"This would be clearly against the material interests of the people of Scotland and put the Union itself at risk.

"They must now demonstrate that it is not true that on the morning after the referendum the Conservative Party stopped thinking about Scotland and started thinking only about the Conservative Party."

First Minister Alex Salmond said: "This is an astonishing development. How can Gordon Brown call for people to sign a petition urging Westminster to keep its promises on more powers for Scotland when he himself has already said that is a vow which will be honoured?

"He is now calling for guarantees on the delivery of something which he himself said during the referendum campaign was already a done deal.

"The 'Tory trap' is not the proposals on income tax which Gordon Brown talks about - it is the Tory trap which he and his colleagues are leading people into, in which the issue of more powers for Scotland becomes entangled in a row between factions of the Westminster establishment.

"Scotland has been promised very substantial new powers, regardless of Tory attempts to link the issue to that of English votes for English laws.

"Many of the people who voted No in the referendum did so in the belief that those new powers would be delivered, and that is what now must happen."