Escalations in the row between Catalonia and Spain over the region's bid for independence feature on the front of Sunday's papers.
The Observer reports on how the move by Spanish prime minister Mariano Rajoy to impose direct rule from Madrid has "dramatically escalated Spain's deepest constitutional crisis since the restoration of democracy in 1977".
The Independent shows the "outcry" of Mr Rajoy's plans, with thousands of protesters taking to the streets in Barcelona.
Theresa May also doesn't escape the front page, with the paper saying that the Prime Minister looks ready to make a U-turn on draft proposals to cap energy prices.
It has reportedly learned that the plan could be ditched if the Big Six energy firms are found to be doing enough to combat expensive bills.
The Sunday Times also features the events in Spain, using a prominent picture of a woman wrapped in a Catalan flag who came out to protest the move.
It also reports on how online gambling sites have been urged to remove adverts likely to appeal to children.
Elsewhere, Catalonia also features on the front page of the Sunday Telegraph alongside a story saying Mrs May is close to "a major climbdown" on Universal Credit, while the Sunday Express leads on plans by Communities Secretary Sajid Javid to tackle "unscrupulous" home-selling techniques.