Looks like Pacha Ranawaka has read the Daily Mail and the Telegraph websites.
Reasons for Labour win were very simple.
1. Boris Johnson was a jackass. He disrespected the Queen by partying during COVID-19. While the Queen was mourning Prince Philip's death, Johnson was having a party. This went down very badly with most Brits.
2. Boris Johnson wanted to hold on to power and he purposefully overlooked senior members and gave high positions to juniors when he chose his cabinet. This is how Rishi Sunak came up.
3. British people hated Sunak because 1. He's Indian 2. He's filthy rich. He has a history of insulting the working class. Once he publicly claimed he has high class friends and working class friends. Then he immediately said "maybe not working class friends". This was an insult to most people.
4. Sunak was also corrupt. He awarded a contract worth millions of pounds to a friend for buying PPE during COVID. This PPE was unusable. His friend bought a luxury yacht with the money.
5. Sunak created a special visa category for Indians. Brits were worried that he will make UK an Indian colony soon.
6. Sunak tried to introduce mandatory military service to young British. This lost millions of votes.
7. Just before elections, Sunak made a stupid statement saying that his family didn't have enough money for Sky TV (Cable TV) when he grew up. Somehow he forgot that his parents sent him to the most expensive private school in UK.
In short, the reason why Labour won is because of Boris the Jackass and the Stinking Sunak.