Newspaper headlines: Parsons Green latest and Tories 'at war'
Several papers feature a picture of the foster parents whose home has been searched as part of the investigation into Friday's Tube bombing.
The Observer interviews neighbours who were told to leave their homes as the operation unfolded, "shattering the peace of a London suburban street".
"I had one minute to get out of the house with my three children," one woman tells the paper.
The Sunday Telegraph highlights a report that warns the EU laws meant to stop terrorists getting the ingredients to make such bombs are too lax.
It says the European Commission has found "alarming" gaps in the way sales of potentially lethal chemicals are controlled.
According to the Sunday Mirror, followers of so-called Islamic State are using an instant messaging site to send encrypted online messages "urging lone-wolf jihadis to carry out atrocities across the UK".
It says fanatics "warned an attack in London was imminent 36 hours before the Parsons Green explosion".
The think tank, the Henry Jackson Society, the former army commander Colonel Richard Kemp, and a leading security expert all take to the Sunday Express to demand greater action to monitor and deport foreign nationals involved in extremism.
The home secretary reflects in the Sun on Sunday on the need for a new security treaty with the EU after Brexit.
Amber Rudd says continued close co-operation is vital, and announces that the government will set out its plans for a new partnership on Monday.
She says the EU already has agreements with non-EU countries on law enforcement and expresses confidence that an understanding can be reached.
The fallout from Boris Johnson's intervention on Brexit continues, amid claims that it is the start of a leadership challenge.
According to the Sunday Express, sources close to the foreign secretary have been forced to deny he is "on manoeuvres" while a Downing Street source points out: "He's going to be given a platform at conference to air his views, so we're not sure why he felt the need to do this."
The Mail on Sunday describes the Conservatives as being "at war", with Boris Johnson in "open revolt" against Theresa May.
A supporter of the foreign secretary likens his comments to "lobbing a hand grenade through Downing Street's window". David Cameron's former speechwriter, Ian Birrell, uses an article in the paper to accuse Mr Johnson of being "disingenuous, disloyal and desperate" to lead the country.
But Mr Johnson's fellow Vote Leave campaigners, Michael Gove and Priti Patel have "thrown their weight behind" his vision, says the Sunday Telegraph. In particular they support his call for some of the money sent to Brussels to be spent on the NHS.
Mr Gove and Mr Johnson are said to have reconciled after their falling out last year and to be "of one mind" on the issue.
The Sunday Times columnist Dominic Lawson argues that Boris Johnson is "self-serving, egotistical...but right" to urge "more Brexit zest" from the government.
And the Sun on Sunday welcomes his involvement as a way of filling what it calls the "pro-Leave vacuum in government" and says his party must listen to him.
A double-page spread on the "Indian summer" of Sir Vince Cable features in the Observer.
As the Liberal Democrats gather for their conference in Bournemouth, "the oldest person to lead a British political party since Winston Churchill" describes how he had assumed, six months ago, that his political exile was permanent.
But, now that he is at the helm, he says he is determined that his is not merely "a plucky third party" but a "serious party with a serious leader" who could be prime minister.
Fat seats for footie
Meanwhile, the Sunday Times says the chancellor is considering "slashing" tuition fees to £7,500. The paper reports the proposals are being drawn up for the autumn Budget amid frustration that some universities are not offering value for money.
And finally, overweight football fans are being offered extra-large seats at next year's World Cup finals reports the Mail on Sunday.
The paper believes it is the first time seats at a major sporting event have been made bigger because of the obesity crisis.
It says those hoping to take advantage of the extra space will have to produce evidence, such as a doctor's note, confirming that they have a BMI of 35 or above.