Virgin media: virginmedia.com/shop/broadband…
BT: home.bt.com/tech-gadgets/i…
TalkTalk: talktalk.co.uk/shop/security/…
There are loads more! Whoever provides your internet should give you the tools to block certain types of site (and individual sites). Take time to explore it in lockdown if you're worried.
O2: parentalcontrol.o2.co.uk
EE: ee.co.uk/help/help-new/…
+ more. Go look on your ISP's website, find the content controls, have a play.