Johnson unity plea after defections
Boris Johnson led efforts to rally Tories behind David Cameron's Europe policy after his own former deputy became the latest to defect to Ukip.
The London mayor told Conservative activists at the party's conference that victory was "within our grasp" if it could remain united in the face of the threat from Nigel Farage's eurosceptics.
In determined show of loyalty, he said Mr Cameron was the only leader who could deliver a referendum on the UK's EU membership and urged Tories to "eat the 'Kippers for breakfast".
As Europe continued to deflect attention from efforts to present to voters a raft of pre-election promises on the NHS, fighting extremism and the economy, Mr Cameron admitted he had "a fight on my hands" to win back supporters lost to Ukip.
Eurosceptics were cheered by the PM's declaration that he would not be "heartbroken" if he failed to keep Britain in the EU - saying he had felt "a thousand times more strongly" about preventing Scotland leaving the United Kingdom.
But he continued to resist mounting calls to say whether he would lead the campaign to withdraw should he fail to secure sufficient reforms to the UK's relationship in negotiations with EU partners in the run-up to the promised 2017 in/out vote.
Pressed repeatedly in an interview on the BBC to say what his "Plan B" would be, he insisted he was confident of success.
"Do you go into a renegotiation saying 'I can't possibly hope to succeed'?," he told the BBC.
He was backed by Chancellor George Osborne who told activists gathered in Birmingham for the last time before next year's general election: "In politics you've got to go out and fight for what you want, not what you don't want."
Mr Cameron dismissed the defection of former London deputy mayor Richard Barnes as not "particularly significant" and said it was "unnecessary and counter-productive" like those of MPs Douglas Carswell and Mark Reckless.
But he accepted the need - set out by Mr Johnson - for more efforts to reunite the "Conservative family" of voters on the centre-right and right.
"If you are saying to me 'You've got a challenge to beat Labour on the economy and prove that they can't deliver, but at the same time you need people contemplating Ukip to come back into the Conservative fold, to deliver immigration control, to deliver an in/out referendum, to deliver a low-tax economy', I completely agree.
"If you are saying I've got a fight on my hands, yes, I have."
Questions over Europe threatened to overshadow Mr Cameron's bid to counter Labour pledges to boost NHS funding by promised "many more" family doctors after the general election to deliver a pledge of extended-hours access to a GP seven days a week for every NHS patient in England.
He said another £100 million would be made available from April 2015 to extend more flexible services across the country and promised a return to patients having an individual named family doctor.
Doctors' leaders warned significant additional funds and resources were required and shadow health secretary Andy Burnham said the it had become harder to see a GP under this Government despite repeated promises.
"His broken promises on the NHS have caught up with him," he said.
Theresa May burnished her credentials as a contender to succeed Mr Cameron as party leader with a wide-ranging speech in which she declared "British values" would prevail in the fight against extremism.
She said a post-2015 Tory government would introduce new "banning orders" to help the authorities tackle groups that are not covered by existing terror laws and "extremist disruption orders" to tackle those "who stay just within the law but still spread poisonous hatred".
But senior Tories raised concerns about the proposals and Mrs May became embroiled in a bitter battle with the Liberal Democrats after accusing the junior coalition government partner of putting lives in danger with an "outrageously irresponsible" opposition to enhanced surveillance powers for the security services.
Mrs May said that in six months the National Crime Agency dropped at least 20 cases as a result of missing communications data, 13 of which involved a threat to the life of a child, while the Metropolitan Police over a three month period had to drop 12 cases including sexual offences and potentially life threatening scenarios relating to a "suicide threat" and a kidnap.
A Lib Dem spokesman accused her of "peddling misinformation in a vain attempt to get the so-called 'snooper's charter' back on the table.
"We utterly reject the allegation that the blocking of the Communications Data Bill has put lives at risk," he said.
"Police already have the ability to obtain data in urgent cases where lives are in danger.
"If failure to act on the IP matching problem has put lives at risk, the Home Secretary must explain why her department has not acted."
Tory former shadow home secretary David Davis warned Mrs May she faced "real trouble" getting the new orders approved by parliament and the courts - dubbing them "quite incredible powers to limit democratic rights".
And ex-attorney general Dominic Grieve QC said that "any restriction on freedom of expression of individuals outside of the criminal law is something that has to be approached with very great caution".
Julian Huppert, Lib Dem MP for Cambridge, he was "utterly dismayed" with her suggestion that the Lib Dems had put children's lives at risk.
He asked her to issue a public correction and an apology as soon as possible.
In a letter to the Home Secretary, Mr Huppert said: "T hat is an extraordinary claim and one which must be backed with compelling evidence. Instead, you cited figures from the National Crime Agency which were entirely misleading."
He went on: " The National Crime Agency cases you cite were, I understand, unable to proceed because it was not possible to connect the IP address used for the communication to a particular device. 'IP matching' is a genuine problem, and as you know, Liberal Democrats have supported and continue to support action to solve it. Following our vetoing of the Communications Data Bill, we supported including proposals to resolve this problem in the Queen's Speech.
"Since then, nothing has happened. No such proposals have been brought forward by your department.
"Responsibility for the lack of data in the cases you cite, and the risk thereby caused to individuals, including children, therefore lies exclusively at your door. It has nothing whatsoever to do with the Liberal Democrats.
"I realise that your conference speeches are not subject to the same levels of accuracy as statements in the House of Commons, but nonetheless I would expect you to issue a public correction and an apology at the earliest opportunity."