Prince George and Theresa May were identified as terror attack targets in two court hearings on Wednesday, as the head of Scotland Yard warned that an increased terror threat in England was straining police resources.
On Wednesday, three men were remanded in custody after appearing in London's Westminster Magistrates Court on terror charges.
Husnain Rashid, 31, used an encrypted online chat channel to urge terrorists to attack Prince George, showing them a picture of the prince at the beginning of the school term next to a silhouetted ISIS fighter, prosecutor Rebecca Mundy said.
The picture included the address of the prince's school and the message "even the royal family won't be left alone".
He allegedly set up the channel on the app Telegram to help would-be attackers with guides, tips, and suggested targets - including a list of UK sports stadiums.
In a separate hearing, Naa'imur Zakariyah Rahman, 20, appeared briefly, charged with planning to set off a homemade bomb at the Downing Street gates and attack Prime Minister Theresa May with a knife and suicide vest.
Rahman, who described himself as Bangladeshi-British, was charged with the preparation of terrorist acts. He was also charged with assisting another man, 21-year-old Mohammad Aqib Imran, in preparing a separate act of terrorism.
MI5 and counter-terror police say they have thwarted 22 terror plots in the last four years. However there are still around 600 counter-terror investigations under way, with more than 3000 "individuals of concern".
On Wednesday, the head of London's Metropolitan Police, Cressida Dick, gave a briefing to the foreign press, including Fairfax Media, in which she said she had been shocked by the "summer of terror" in London.
"The threat has increased, this is not a small spike this is a shift," she said. "It translates into greater workloads for our people.
"Clearly the increased (terror) threat, the increased tempo puts an increased strain on the system and requires even cleverer??? juggling and even better use of the technology and data that we have got."
The Met's Counter Terrorism Command had seen a 30 per cent jump in their workload in the last year, she said.
"There are a number of factors that have played into this (increased threat), one of which is clearly the speed of communication and the way in which Daesh in particular have used social media to inspire and encourage," Dick said.
When you look at the attacks that have been made public - as well as those plots still under investigation - they have very different characteristics, she said.
"They are very different types of people with different backgrounds??? This multi-dimensional - from overseas, at home, online - threat is something that most countries are having to wrestle with."
The Met needed to tighten its relationship with intelligence agencies, she said - a recommendation that came out of an internal review that was approved by a public, independent review published on Tuesday.
Dean Haydon, the head of the Counter Terrorism Command at Scotland Yard, said the six attacks this year in England at Westminster, London Bridge, Manchester, Finsbury Park, Buckingham Palace and Parsons Green were mostly by lone actors.
"Every single one is different, with different motives, different ideology," he said. "If there is any reassurance, they are not linked."
Similarly, Dick said, the nine plots disrupted this year since March were all "quite different in their flavour".
Police would do a "whole range of things differently and better" if there was another terror attack but generally their response to each plot had been excellent and saved lives, Dick said.
She wants to increase the number of officers carrying Tasers, so that in a couple of years time a majority of officers will have them.
Tasers were a "very effective tool" and, as well as potential use in terror response, they helped calm down situations in general policing, she said.
Dick said her job meant "you have to constantly juggle your resources", and almost every day police had to make a decision as to where best to put their anti-terror surveillance teams according to the latest threat assessments.
On top of that, the Grenfell Tower disaster had involved 400 police officers, and there were still 200 working on the resulting investigation.
And there were still other concerns. "I could put the whole of the Metropolitan Police on the issue of sexual images online and it would still take a very long time to deal with all of the offending that might be out there," she said.
Dick said it had been a "shocking" year for the city and the country, but she was proud of the police response, and had "really ambitious plans" for 2018.