British soldiers are at risk from "thousands" of lone wolf terrorists such as the Islamist fanatics who murdered Drummer Lee Rigby, the country's most senior counter-terrorism officers have warned.
Assistant Metropolitan Commissioner Cressida Dick said troops will always be a target for those with a "perverted ideology" and the threat can never be eliminated.
The warning came as Muslim converts Michael Adebolajo (29) and Michael Adebowale (22) were yesterday convicted of the murder of 25-year-old Fusilier Rigby.
Adebolajo showed no remorse and kissed his Koran as he was found guilty at the Old Bailey.
The pair ran the father-of-one down in the street in broad daylight before hacking him to death and dumping his body in the road in what was the first terror-releated murder on British soil since the July 7 bombings in 2005.
As they faced life in prison:
* Questions intensified over whether MI5 and the police could have done more to prevent the murder by two fanatics who were known to them.
* Security sources revealed others almost certainly knew of their plot to kill a soldier.
* The family of Mr Rigby spoke of their devastation and suggested his killers should be treated the same way he was.
* Police vowed to monitor every word of hate preachers like Anjem Choudary, who helped radicalise the pair, to see if prosecutions can be brought.
* Muslim leaders condemned their actions, saying it was a "barbaric act".
The death of Drummer Rigby was the latest in a series of terror plots to target British soldiers, often in so-called revenge for Britain's foreign policy.
Asst Comm Dick said: "Every year we've stopped a major plot designed to cause mass murder, and trials earlier this year of people intending to kill people on the streets of the UK including soldiers.
"Sadly we know that some people have a completely perverted ideology and do regard soldiers as a target.
"It's important that we recognise that and try to protect our military colleagues as best we possibly can.
But she added: "There are thousands of people who are subject to security service interest and investigations."
"We cannot reduce the risk of something like this happening to absolute zero but we will do everything in our power to do so."
In October, Andrew Parker, the director general of MI5, warned the UK was facing its gravest terrorism threat, including from "several thousand" Islamist extremists who are living here and want to attack the country.
In 2007, a terror gang led by Parviz Khan discussed kidnapping a Muslim British soldier, beheading him "like a pig" and then posting film of the killing online.
In April this year, Muslim convert Richard Dart was jailed alongside Jahangir Alom and Imran Mahmood, for plotting to stage an atrocity in Royal Wootton Bassett, where mourners paid their respects to British troops killed in Afghanistan.
That same month Zahid Iqbal, Mohammed Ahmed, Syed Hussain and Umar Arshad, all British and from Luton, were jailed for plotting to bomb a Territorial Army base by driving a remote-controlled car packed with explosives under its gate.
Also this year, three Birmingham jihadists led by Irfan Naseer received lengthy prison sentences after discussing using suicide vests, rucksack bombs and guns to kill innocent people, including British soldiers.
Security sources fear associates of Adebolajo and Adebowale knew of their plot, even if they were not part of it.
One senior Whitehall source said: "You would struggle to find anyone who thinks no one else knew what they were going to do.
"It would be very, very unusual but the key is whether there is evidence to point there."
Another said: "It has to be a possibility. I do not see how it is possible to rule that out. The frustration is finding the threshold for a realistic prosecution."
Adebolajo's brother, Jeremiah, told Al Jazeera: "The events to me were inevitable. There was eventually going to be another attack which mentioned foreign policy as its justification."
"I suggest that it won't be the last, simply because of the tactics of the British secret service and foreign policy... for every violent action, is a violent reaction."
Fusilier Rigby, who had only ever wanted to be a soldier, was virtually decapitated in a brutal assault involving a meat cleaver and knives, as he returned to his barracks in Woolwich, south east London, on May 22.
Adebolajo and Adebowale had driven around for an hour looking for a soldier target and chose Mr Rigby because he was wearing a Help for Heroes hooded top and carrying a camouflage rucksack.
After the barbarous act, Adebolajo, still clutching a cleaver and with blood on his hands, was recorded telling terrified onlookers it was an "eye for eye" because British soldiers were killing Muslims overseas.