In the US, a 4% differential is called a landslide.
This is a rout.

But HOW did Reform get more seats than SNP?

The final numbers skew even more toward Labour: 412 seats vs 121 for Conservatives.

https://www.cnn.com/2024/07/04/uk/uk-election-results-tracker-map-2024-intl/index.html

Reform get "only" 4. Better than 13, worse than zero.

And Greens now have 4 seats!
But they have 6.8% of the popular vote: under proportional representation they would have 44 seats. Forty-four! Shows you how undemocratic that "first past the post" system is, separated by voting district.
OTOH Reform would have had a lot more seats as well.

2024 UK general election results in graphics

The tectonic plates of British politics have shifted after Britons resoundingly voted to put an end to 14 years of Conservative rule, and deliver a landslide victory for the Labour Party.

CNN

Here's the Guardian gloating a bit over high profile Tories who lost their seats.

https://www.theguardian.com/politics/article/2024/jul/05/2024-election-portillo-moments-which-big-beasts-have-lost-their-seats

[Edit to add;] I feel the gloat. Yes I do.

The 2024 election’s ‘Portillo moments’: which ‘Big Beasts’ have lost their seats?

Defeats of Penny Mordaunt, Gillian Keegan, Grant Shapps and Liz Truss among the jaw-dropping moments of election night

The Guardian