But, alarming though this news is, does it justify, as one senior cabinet minister has suggested, prosecuting those who are accused of planning terror acts under the laws of treason?
There can be little doubt that Islamic State (IS), the extreme fundamentalist sect against which war is now being waged in Syria and Iraq, poses a terrorist threat unlike any that Britain and the rest of the western world have so far faced. Some of the suspects implicated in the terror cases which have gone to court are people who have returned to Britain after being trained in merciless terror by IS and seem clearly intent on putting into practice what they have learned in the Middle East.
Radicalised by what they have learned from extremist preaching over the internet, perhaps as many as 2,000 mostly young British Muslims, including about 60 young women, have heeded the siren call of IS and headed to the Middle East. A few have been sickened by their experience there, but far too many have not.
The dreadful likelihood of the ghastly beheadings that seems to be the dreadful trademark of IS being repeated on British streets, along with shootings and bombings seems only too real, particularly as it seems probable that many recruits to the IS cause may also take up their methods without leaving Britain’s shores or may be recruited by returnees.
Britain clearly needs to be ready to respond to this challenge. It is already putting available counter-terror officers under severe strain, and if more resources need to be allocated to them, either to train additional staff or to gain the equipment they need, so be it.
But what use would it serve, as Philip Hammond, the foreign secretary has suggested, for those caught planning such offences to be charged under treason laws? These were last used more than half a century ago to prosecute William Joyce, who became notorious for broadcasting propaganda from Nazi Germany during the Second World War.
It would hardly be a deterrent. Despite popular mythology, treason is not punishable in the UK by the death penalty but by a sentence of up to life imprisonment, the same as for murder. And to committed jihadists, knowing that a charge of treason to a state that they wish should be destroyed may await is hardly likely to make them think twice.
Rather it looks like a sign of panic amongst politicians who have no clear idea of how to handle this particular threat within existing legal and moral boundaries.
A firm resolve and necessary resources are needed, but Britain is not engaged in a war with national survival at stake, necessitating suspension of normal ways of life.
Vinyl discs slip back into fashion
Click, pop, crackle. To modern music lovers, the days when playing recorded music meant placing a foot-wide circular piece of vinyl plastic on a turntable, carefully lowering an arm so a needle could slot into near-invisible grooves, and putting up with irritating noises caused by dust or scratches in the grooves, must seem as sensible as using a penny-farthing to go for a mountain bike ride.
When something less bulky than a cigarette packet can contain an entire library of favourite music and deliver a pretty high quality sound into ears while the listener can be sitting, running, driving, working, or atop a mountain with no electricity, the idea of vinyl discs seems preposterous.
And yet not only have they refused to go away, they seem to be making a comeback. Since 2007, when they looked deader than fax machines, sales of vinyl discs have been rising and this year they may pass the 1 million mark in Britain, a trend that is occurring world-wide.
Some music purists claim that, properly looked after, vinyl recordings can have a depth and tonality that is unmatched by digital players, though connoisseurs of digital music at the more expensive end of the market snort that this is complete nonsense.
Seven years of rising sales say that this is not a passing fad. Maybe it is a quality thing, like Harris tweed, which has gone through a slump or two, but keeps on bouncing back into favour. Or maybe it is a modern retro fashion with some folk liking to show off Beatles albums as they used to be. Whatever, it is somehow comforting to know there are some things which technology cannot render extinct.