Boris Johnson vowed to "eat the 'Kippers for breakfast" as he sought to unite Tories and lambasted those who had defected to Ukip.
Mr Johnson hit back at "quitters and splitters" and told activists that victory in next year's general election was "within our grasp" as long as the party remained united.
To loud cheers the Mayor of London said:
Just before I begin can I check that we are all proud Conservatives? Proud of the oldest and most successful party in all the Western democracies? Do we intend to fight the next election under the Conservative banner and no others? Are there any quitters or splitters? Anyone feeling a bit yellow around the edges - like a kipper?
Only the Conservative could deliver reform to the UK's relationship with the EU, he said. Comparing the successful fight against Scottish independence with the imminent by-election battles to retain the seats given up by defecting MPs Douglas Carswell and Mark Reckless, he said:
That's our new fisheries policy, folks. First chuck Salmond overboard and then eat the 'Kippers for breakfast. We will fight them on the beaches of Clacton and of Rochester and Strood as well.
A senior Conservative Eurosceptic has reportedly warned businesses that they will pay a "very dear economic and financial price" if they speak out in favour of Britain staying in the European Union.
According to the Telegraph, former minister John Redwood told a fringe event at the Conservative Party Conference that firms should "keep out" of the debate and "not meddle in politics".
The newspaper quotes Redwood as saying: "If they don't understand that now they will find those of us organising the 'get out' campaign will then make life difficult for them by making sure that their customers, their employees and their shareholders who disagree with them - and there will be a lot who disagree with them - will be expressing their views very forcefully and will be destablising their corporate governance."
George Osborne has joked that Ed Miliband's speech to last week's Labour Party conference was "so forgettable, he forgot it himself".
Mr Miliband forgot a key passage on the deficit, something the Chancellor said was a "disqualification for the high office he seeks".
A Conservative MP has said he will write the police over newspaper "entrapment" that led his Conservative colleague Brooks Newmark to resign from government.
Mark Pritchard had already confirmed he would be complaining to the new press regulator about the Sunday Mirror revelations, but has now questioned whether criminal law was also broken by the newspaper.
Test for IPSO and Met Police. I will write to both today about Sunday Mirror story. Was the criminal law and IPSO Code of Conduct broken?
Brooks Newmark resigned as Minister for Civil Society after he sent suggestive pictures to a reporter posing as a young Conservative campaigner.
Conservative voters considering voting for Ukip face the reality of a choice between David Cameron or Ed Miliband, George Osborne has told Good Morning Britain.
The Chancellor said people may be looking for "easy answers" following the recent recession, but said the coalition's plan for the economy was working and would lure voters back.
A Conservative MP says he will complain to the newly-formed press regulator over the "entrapment" that led to his colleague's resignation as a government minister.
Brooks Newmark resigned as Minister for Civil Society after Sunday Mirror revelations that he had exchanged suggestive pictures with a reporter posing as a young Tory campaigner.
Following the story's publication, fellow MP Mark Pritchard said he would be referring the newspaper to the Independent Press Standards Organisation (Ipso).
Pritchard told the BBC: "It is in the public interest that their actions are fully investigated. This is the first real test as to whether the new body, Ipso, has any teeth."
Boris Johnson is "a real Conservative star" who will be a welcome addition to the Tory team fighting the next general election, George Osborne has told Good Morning Britain.
Responding to polling indicating that the London mayor would be a more popular leader of the party than David Cameron, the Chancellor said: "We want the best team on the pitch. We want Boris as our striker on the pitch and that is what he is going to do under the leadership of David Cameron."
The mood at the Conservative party conference is "very positive", as it gears up for its most high profile meeting before the next general election, an influential Tory MP said.
Nigel Evans told Good Morning Britain: "The mood of the Conservative party is that we can win that next general election. It's only a few months away but because of all the things that have happened - the turnaround in the economy and the very positive mood we have here."
London mayor Boris Johnson has issued an appeal to would-be Tory defectors urging them not to break ranks and join Ukip.
Writing in his weekly column in The Daily Telegraph, he said Conservative MPs would be "utterly nuts" to desert the party as they simply risked handing power to Labour at the next general election.
Mr Johnson said he thought reports that two or three more MPs were preparing to follow defector Mark Reckless and jump ship were "fanciful".
But he wrote: "Let me try to reason with any in my party, the folk who want to launch themselves headlong into the silage, because I genuinely think that they (if they indeed exist) must be utterly nuts.
"There are only two people who are in a position to take the keys to Downing Street next May, and they are David Cameron or Ed Miliband.
"If you really want to let this country sleepwalk into a Labour government, then that is your prerogative. You can close your eyes and let it happen. You kip if you want to; the rest of us are going to fight and win."
A third of voters in 40 marginal seats would consider voting for Ukip at the next general election but over half said they would next cast their ballot for the eurosceptic party, a new ComRes poll for ITV News suggests.
In the event of a coalition government after the next election, voters would prefer the Liberal Democrats to Ukip as the junior partner by 42% compared to 35%.
Conservative voters also preferred to work with the Lib Dems instead of Ukip by 47% to 40%.