I don't believe there was a plot to cause "mass murder on an unimaginable scale" using liquid explosives carried onto planes as hand luggage, just because the British police say so. With their appalling record of credibility, they need to show me some real evidence before I decide to become officially terrorised.
Their record on this sort of thing is bad. First there was the tragic case of Jean Charles de Menezes, the Brazilian man shot dead because police misinformation suggested he could have been a suicide bomber. He wasn't. The police officer who should have advised this was having a piss at the time, thus allowing the mistake to be made.
Later there was the case of the Kahar brothers whose London home was raided, and one of them shot, because police had supposedly reliable information they were making a chemical bomb. Weeks later the search turned up nothing and the pair was released.
Now we have police and politicians scaring us with tales of an imminent plot. Police breathlessly and laughably said tens of thousands of people could have died. They later toned it down to "hundreds". The theory about liquid explosives has been widely reported. But some explosives experts say it would have been quite difficult to make the liquid bombs allegedly planned. To effectively assemble such explosives may prove, in practice, to be impossible. Yet some media reports said the attack could have been days away, and the United States went to maximum terror alert. http://www.guardian.co.uk/terrorism/story/0,,1853741,00.html
Careers are being built on this, security empires are growing, and political skins are being saved. A day after the plot, George W Bush was claiming it justified a range of global policies, including the war in Iraq and Israel's actions in South Lebanon.
Terrorism is really bad, no doubt about it. So it's terrible when someone makes a prank call, saying there's a bomb on a plance and disrupting people's lives. The British police have been found out making the law enforcement equivalent of a prank call, only with much worse consequences.