Welsh devolution: Tax powers 'will fight Scottish yes vote'
First Minister Carwyn Jones has called on the chancellor to give Wales tax-raising powers to help defeat the pro-independence lobby in Scotland.
He urged George Osborne to show that UK administrations opposed to Scottish independence can work together.
The Silk Commission considering further devolution has said there is a strong case for giving limited tax and borrowing powers to Wales.
It would be up to the UK government to legislate them into force.
BBC Wales understands that Mr Jones is urging the chancellor to use the Silk Commission recommendations to show devolved funding can be successfully reformed from within the UK.
All four parties within the Welsh assembly endorse Paul Silk's findings.
Mr Jones is a strong opponent of Scottish independence and believes that Wales can play a significant role in making the case for Scotland to stay within the UK.
However, the Welsh government is increasingly frustrated that UK government ministers still have not formally responded to the Silk report.
Mr Jones has written to Mr Osborne warning him that a failure to implement tax and borrowing powers for Wales could make a yes vote in the Scottish independence referendum more likely.
In his letter, the first minister warns the chancellor that if the UK government is seen to be dragging its feet on giving more powers to Wales, this could provide ammunition for the pro-independence campaign ahead of the referendum in Scotland on 18 September next year.
He has appealed to Mr Osborne to show that other UK administrations which are against Scottish independence can work together.
It is understood there is unlikely to be a new Wales Bill implementing the Silk proposals in the list of proposed legislation announced in the Queen's Speech on 8 May.
In his speech to the Liberal Democrat conference earlier this month, the Chief Secretary to the Treasury Danny Alexander said he would "not allow" a response to Silk that did not deliver significant new financial accountability for Wales.
But this has led some to question whether the coalition at Westminster is split over the extent to which Wales should be allowed to raise some taxes and borrow money for big infrastructure projects.