Newspaper headlines: Focus on Westminster terror arrest
The front pages are dominated by the image of the man arrested on suspicion of terrorism offences in Westminster.
The Daily Telegraph says his family had become concerned about his behaviour and reported him to the authorities several weeks ago.
It says he had been followed on the London Underground and was stopped as he approached Downing Street. Police tell the paper he is thought to have been a "lone wolf".
The Times reports that he is thought to have been mixing in radical circles for some time, adding that he had been "allowed to run" by the intelligence services in an effort to gather evidence about an apparent plot.
The tabloids make much of the way he looks at the photographer as he was being detained.
The Daily Mirror describes it as the "Smirk of the Parliament copycat knife suspect", noting that he was stopped "just yards from last month's Westminster terrorist atrocity" in possession of knives.
The Daily Express is impressed with the "restraint, good judgement and calm heads" shown by the officers, adding that the speed with which he was identified and arrested is "immensely reassuring".
Anthony Glees, the director of the Centre for Security and Intelligence Studies at Buckingham University, says the security services need thousands more officers to confront the problem.
Elsewhere, the i says intelligence agencies have uncovered the last message left by the man responsible for last month's killings in Westminster, Khalid Masood.
He is said to have revealed his motivation on the messaging service WhatsApp, declaring that he was "waging jihad" in revenge for Western military action in the Middle East.
The paper says the person who received the message was questioned and released.
Regulator with bite
In other front page stories, the Daily Mirror says head teachers are warning their school budgets will soon become untenable.
The paper prints an open letter they have written to Theresa May, demanding that she scraps plans for education cuts. The letter urges her to "stop seeing education as a cost and instead see it as an investment in the future".
The Financial Times says Irish diplomats are asking EU leaders to endorse plans for Northern Ireland to rejoin the bloc in the event of a vote for reunification with Ireland.
It says the prospect of a referendum on the issue is allowed for in the Good Friday Agreement but the idea will "reinforce the fears of those in Britain who believe that Brexit will bolster those championing the break-up of the UK".
According to the Times, the NSPCC wants social media companies such as Facebook and Twitter to be fined if they fail to protect children online from harmful content.
In a letter published in the paper, the charity's chief executive, Peter Wanless, urges the next government to establish a "regulator with bite" to monitor the sites, and to introduce similar rules and age ratings as those used in the film industry.
The Guardian features a special report from the "sleepy farming village" in South Korea which has been transformed overnight by the arrival of components for a new US missile defence system.
Its correspondent, Justin McCurry, says residents of Seongju are angry about being on "Korea's new frontline".
One man explains that they usually "welcome outsiders with open arms" but fears the arrival of American weapons is turning them into a target for North Korea.
Paul Dadge was photographed leading a woman holding a burns mask to her face - an image that it says came to symbolise the attacks.
Researchers from Chicago have concluded that Europe's queens of the past 500 years had more appetite "for war, slaughter and mayhem" than the kings and have been more effective at winning.
The married monarchs were the most warlike because they were happy to leave their husbands to manage the state while they set out to defeat their enemies.