Will Miliband use his lifeline in PMQs?

At the weekend, Tories were anticipating giving Ed Miliband an almighty kicking at PMQs. Lord Glasman’s description of Labour’s economic record as ‘all crap’ had given them a killer line. As one member of the Cameron circle joked to me, ‘we’ve never had more material to work with.’ 
 
But Ed Miliband now has a get out of jail free card. If he asks six questions about the Union and the referendum, it will be impossible for Cameron to have a pop at him without looking distinctly unstatesmanlike. On Scotland, the two leaders need each other. The Unionist side cannot win without the Labour party and the Labour party will find it very hard to win general elections without Scotland.
 
The question is whether Miliband chooses to take this out or not. There’ll be those saying it would be a sign of weakness to do so. But given that the very existence of the United Kingdom is at stake, Miliband could hardly be criticised for leading on the referendum.