In the United Kingdom, by-elections were held in three constituencies, whose representatives in the House of Commons had resigned in recent months: a politician from the Labor Party (centre-left), one from the Liberal Democrats (centre) and one from the Conservative Party (centre-right) were elected. The resigned MPs were all from the Conservative Party: among them was former Prime Minister Boris Johnson, who resigned in June following a scandal over the violation of restrictions to combat the coronavirus pandemic.
In the British electoral system, each MP represents a constituency corresponding to a specific geographical area. Each time a seat becomes vacant, the voters of the constituency linked to that seat must elect a new representative.
The constituency in which Johnson was elected was the only one in which the Conservative Party, which has been the prime minister since 2010, managed to maintain a majority: for several months the government has been in a lot of trouble in the polls.