First poll since Cameron's EU referendum pledge shows Labour's lead has risen two points to 12.
Tory unity will prove shortlived and the Labour leader could execute a relatively painless U-turn on a referendum.
If Miliband matches Cameron's referendum offer, he will look weak. If he doesn't, he will look undemocratic. Which will he choose?
Read the Prime Minister's speech promising to renegotiate Britain's membership of the EU and hold a referendum in 2017.
The questions the PM will face on renegotiation, the referendum and withdrawal.
Any political high from Cameron's EU speech could be shortlived if figures released on Friday show that the UK economy shrunk in the final quarter of 2012.
Speech now scheduled for Monday would coincide with the US president's public swearing-in ceremony.
The shadow foreign secretary says that only Labour can "give voice to the national interest" in an address at Chatham House.
Prime Minister will remain in London tomorrow to chair Cobra meetings, rather than delivering long-delayed speech in the Netherlands on Britain's EU membership.
Labour leader says he would not reverse measure previously denounced by his party as a "dog's breakfast" and a "political gesture".