Says Martin Kettle (with my emphasis),

“Reports that Labour is braced for defeat in Ian Gibson's old seat are entirely accurate. So braced, in fact, that officials have begun floating the absurd idea that anything less that a 10,000 Tory majority – something the Tories did not even manage in 1987 – would be a setback for Cameron.  Some setback.”

Well, let us sit back and see how the Toryphobics try to spin the Norwich North result.