Davis says he will contest the seat to take a stand on the erosion of civil liberties caused by the proposal to extend to 42 days the time police can hold terrorism suspects without charge.

The opposition Liberal Democrats — who also oppose the extension — have already said they will not field a candidate, leaving the by-election a clear contest between Davis and a Labour opponent.

But the high risk move has already lost Davis his shadow cabinet post — he has been replaced by shadow attorney general Dominic Grieve — and could backfire if Labour is able to portray it as a split at the top of Cameron’s party.

Is Davis being courageous? Or just foolish?

Governments, private security companies and law enforcement agencies all play a part in tackling cyber-crime.

But author and academic Jonathan Zittrain argues that we should be wary of “locking down” the Internet with increasing amounts of centralised rules and sealed gadgets that can’t be tinkered with.

In a new book published by Penguin and Yale University Press, he says part of the answer lies in greater freedom and trust, rather than more rules or technological solutions.

We don’t have police on every street corner in the real world, so why have that online, he asks?

People should be encouraged to see themselves as “netizens” — active participants in the online world, rather than passive consumers of Internet content.

They could share the load of policing the net, reporting threats and working together to combat the risks.

He says Wikipedia has shown that online collaboration can work.

“The challenge to the technologists is to build technologies to let people of good faith help without having to devote their lives to it,” he says.

Supporters say it’s just common sense, while at least one critic has described the approach as “utopian”. Who do you think should shoulder the burden of Internet security?

Then there was “spear phishing” - more sophisticated, targeted attempts to defraud specific organisations or their customers.

Now online fraudsters are trying to land even bigger catches by harpooning company bosses and their senior managers.

This latest and most audacious technique is called “whaling”

Fraudsters attempt to lure executives to reveal sensitive details about their business or click on a link in an email that will secretly download malicious software onto their computer.

Criminals could then attempt to defraud the company using the information they quietly gather.

Guy Bunker of Symantec, the Internet security company, says: “Whaling is basically going after the big fish in the sea. It’s targeting people at the top of the organisation.”

“There have been attacks in the States where a whole bunch of CEOs get sent a very official looking email that say you’ve been subpoenaed in court. If you click on this link you’ll get the citation.”

The link was the bait and the boss has exposed his corporation to fraud.

The extent of that problem was laid bare at Infosecurity Europe, an annual computer security conference held in west London.

A government-sponsored survey carried out by PricewaterhouseCoopers said online fraud costs the British economy alone about 6 billion pounds a year.

And with more business carried out online, the problem shows no signs of going away.

Lord Erroll, a technology expert in the House of Lords, told the conference: “The world isn’t going to change with a new generation coming through. It will have gullible and greedy people in it as well.

“So there will be people who do things wrong and are stupid and get conned. Technology alone isn’t going to protect people.”