Tory defector Douglas Carswell said "I stab people in the front, not the back" as he defended his decision to quit the party.
A city-wide 20mph speed limit in Cambridge is a step-closer after it was announced the next stage of limits could be in place by March.
People in Hethersett near Norwich are fighting plans to build homes on land they say is sacred to the village.
The Clacton by-election caused by the defection of Douglas Carswell form the Conservatives to UKIP will be held on Thursday 9 October.
It's the same day as David Cameron's 48th birthday but could be an unwelcome present as polls indicate the Tories face a tough fight to retain the Essex constituency.
An opinion poll in the seat suggested that he enjoys a significant lead and is on track to become the first person to be elected to Parliament for UKIP.
The party's only previous MP, Bob Spink, did not seek a fresh mandate when he defected from the Tories in 2008 in the Castle Point seat in south Essex.
Mr Carswell had been Conservative MP for Clacton since 2010, having previously served as MP for Harwich from 2005-10 before boundary changes.
The Clacton by-election is to be held on October 9, the Conservative Party announced.
The by-election was triggered by Douglas Carswell's defection from the Conservatives to Ukip.
Police forces around the region are on an increased state of alert after the government raised the terrorist threat level from substantial to severe.
It is in response to conflicts in Iraq and Syria.
The former head of the British Army, General Lord Richard Dannatt, who lives in Norfolk, has urged people across the region to be vigilant.
And today a Muslim leader in Luton told ITV News Anglia he feared the raising of the alert could threaten his community.
Serena Sandhu reports.
Tory defector Douglas Carswell has defended his decision to join Ukip and said he hopes voters will stick with him.
Mr Carswell and his new boss Nigel Farage began their charm offensive in Clacton, the constituency they hope will provide Ukip's first MP.
Chancellor George Osborne described the defection as regrettable. But as the MPs resignation became official this afternoon, there were even stronger words from the candidate who was originally due to represent Ukip in Clacton.
Click below to watch Hannah Pettifer's report:
The resignation of Douglas Carswell as Clacton's Member of Parliament has become official a day after he announced he was defecting from the Conservatives to UKIP.
By parliamentary convention set in 1624, MPs can't actually step down from office. Instead they have to apply for one of two offices of the Crown which are incompatible with being an MP.
So on Friday afternoon a message was released by HM Treasury which made Mr Carswell's resignation official:
– HM TREASURY
"The Chancellor of the Exchequer has this day appointed John Douglas Wilson Carswell to be Steward and Bailiff of the Manor of Northstead."
Douglas Carswell has been a Conservative MP since 2005, first as the MP for Harwich and then, after boundary changes, for Clacton.
He announced on Thursday he was quitting the Conservative Party to seek re-election as a UKIP MP in a by-election.
It's not known when the by-election will be held but it usually takes place within three months of there being a vacancy. The date will be decided in Parliament by the Conservative Party Chief Whip, Michael Gove.
Ukip's Roger Lord has said he has no intention of stepping aside for the Conservative defector Douglas Carswell.
The existing general election candidate in Clacton-on-Sea said he 'will not back down'.
George Osborne has labelled the defection of Douglas Carswell to Ukip as "regrettable and counter-productive".
Speaking in Brighton today, the Chancellor said that the best way to secure a referendum on Britain's membership of the European Union was to have a Conservative government after the next election.
"That's the choice people are going to face, whether it's at the by-election in Clacton or at the general election next year," Mr Osborne said.
Nigel Farage has hinted that more MPs could follow Douglas Carswell by defecting to his party before the election.
The Ukip leader said politicians among the Conservative and Labour ranks "feel strongly" on the issues the party stands for.
"I don't think anybody will say that Douglas Carswell coming to Ukip is a one-off.
"There are many other people out there that are making up that calculation now," he added.
Nigel Farage, the Ukip leader, and the party's new candidate for Clacton have been campaigning on the streets of the seaside town this morning.
Douglas Carswell will contest the seat for the eurosceptic party after defecting from the Conservatives yesterday, triggering a by-election for the constituency.