Back to top

The control exists because the top of a page holds things the middle does not: the search field, the primary navigation, the filters that produced the list you are looking at. On a desktop keyboard the Home key already does this and always has. On a phone there is no Home key, the header has usually scrolled away, and the alternative is a dozen flicks, so a single tap that undoes all of them is worth a persistent corner button.

Two decisions make or break it. The first is the threshold. Showing the button immediately is noise, because the top is still on screen and the reader can see it; a common rule is to reveal it after roughly one viewport of scrolling, which is long enough that the top is genuinely gone. Some implementations also hide it again while the reader is scrolling down and bring it back on the first upward scroll, on the theory that scrolling up is the gesture of someone who wants to go back. The second is where it sits. Bottom right is the convention, but it competes with a floating action button, a chat launcher, and a cookie bar, and on a phone it has to clear the home indicator. Overlapping the last line of the footer is the usual symptom of nobody having checked.

Give it a real accessible name, not a bare arrow glyph, and make it a <button> or a link to a #top anchor rather than a decorated <div>. If it moves the page, it should move focus too: a reader using a keyboard who presses it and finds the view at the top but the focus still deep in the document has been stranded. Scrolling smoothly is a nicety that has to be dropped under prefers-reduced-motion, where a long animated flight through the whole document is exactly the motion the preference is asking you not to make.

The GOV.UK version is the honest minimum: a plain “Back to top” link in the flow of long guidance pages, no floating, no fade in. It is worth remembering that the button is compensation. A page that needs one badly is often a page whose navigation should have been sticky, or whose content should have been shorter, and a sticky header quietly removes most of the reason to build it at all.