Scottish independence: Cameron, Miliband and Clegg sign No vote pledge

The three main UK party leaders - David Cameron, Ed Miliband and Nick Clegg - have signed a pledge promising "extensive new powers" for the Scottish Parliament.

It also commits to preserving the Barnett funding formula, which determines the distribution of public spending around the UK.

The "Yes" campaign has argued the only guarantee of more powers is a vote for independence.

Iain Watson reports.