Borrowing essential for M4 work says Carwyn Jones
13 October 2013 Last updated at 10:40 BST
First Minister Carwyn Jones has warned work to improve the M4 will not go ahead if Wales remains unable to borrow money.
The Silk Commission, set up by the UK government to examine devolution, recommended Wales should be given the power when it reported its findings last year.
Mr Jones said it would be a "disaster" for Wales if this did not happen.
Ahead of a meeting of the Joint Ministerial Committee plenary in London on Wednesday, Mr Jones spoke to Radio Wales' Sunday Supplement programme about what he would be saying to the prime minister.