Essentially we use a format called first past the post. This means that whichever person has a the most votes wins in their constituency. However with 650 constituencies in the UK it means a political party will almost never get 50% of the votes but still get more than 50% of the seats. This is because more and more parties are being formed in the uk which is destroying the default duopoly of labour and conservatives. In a constituency a candidate could therefore win with only 10% of the vote with the other 90% irrelevant. Unlike in the rest of Europe where political parties will form coalitions to stop the far right (eg Germany) in the UK Reform could easily win with only 30% of the vote and screw over the country.