Conservative MP Richard Ottaway today announced he will stand down from Parliament at the next general election.
The announcement will inevitably heighten speculation that London Mayor Boris Johnson could put himself forward as candidate for Mr Ottaway's Croydon South constituency as a means of returning to the Commons for an eventual bid for the Conservative leadership.
The seat is a Tory stronghold which Ottaway held by a margin of almost 16,000 votes in 2010.
A YouGov/The Sun survey on the state of the parties gives Labour a 14-point lead over the Conservatives.
It is the first YouGov poll conducted since Miliband's conference speech and the Labour lead has gone up six points since Wednesday.
Figures also show that the proportion of voters that see Ed Miliband as a strong leader has gone up.
- 31% of those questioned thought Miliband was up to the job of prime minister, compared with 25% before the conference.
- The proportion viewing him as a strong leader rose from 16% to 19%.
However, David Cameron still led by a margin of 31% to 27% when people were asked who would be the best PM.
Penny Mordaunt, Conservative MP for Portsmouth North, said she was "very disappointed" in Nick Clegg's response to the dissent over House of Lords reform.
Chancellor George Osborne said the Government would "cross any issues with the boundary vote when we get to them": He said:
"We have not been able to proceed on Lords reform, frankly, because there is opposition in Parliament and the opportunism of the Labour Party would not allow the time for the House of Lords Bill.
I think we have got to use this moment as an opportunity to focus 110% on the economy - which is what the country wants."
Deputy leader of the Liberal Democrats Simon Hughes said although the Conservative MPs' decision not to back House of Lords reform was a "major failure", "life goes on" when it comes to the coalition.
Nick Clegg says plans to reform the House of Lords will be abandoned after the coalition contract was "broken" by the Conservatives.Read the full story ›
Former Liberal Democrat chief executive Lord Rennard said Nick Clegg has acted "swiftly and decisively, even ruthlessly" to "redress the balance" within the coalition government.
@nick_clegg right to have fought for more democracy, right to recognise that Tory MPs blocked deal and Labour wouldn't support reform.
@nick_clegg rIght not to let Tories have what they want from coalition on boundaries if they can't stick to 'contract' on democracy in Lords
Things happen like this in coalitions all the time its in the nature of the beast. Smart thing now is to agree a new 2 year plan fast
Shadow Justice Secretary Sadiq Khan called Nick Clegg's announcement on House of Lords reform and parliamentary boundaries a "humiliation" for the government and a "spectacular failure" of leadership from the prime minister.
David Cameron's weakness in not being able to control his own party and deliver on the coalition agreement shows a prime minister lacking the leadership our country deserves. Nick Clegg seems to be the only man in the country who doesn't understand that.
Although it is not our number one priority, Labour remains fully committed to Lords reform.
As we warned continually, the real obstacle to Lords reform are the Tories. They have never been serious about reform, despite this being in their manifesto. That's why it is outrageous of Nick Clegg to blame Labour.
Delighted that the Conservative plans for #gerrymandering parliamentary boundaries will not now be going ahead, well said Nick!