What is Westminster? Westminster is the name people give to the Houses of Parliament. This is the Parliament for the UK government. The Houses of Parliament or UK Parliament is in charge of all the things that are not devolved. This includes things like defence and immigration and nearly all of the economy. It is sometimes called Westminster because it is in the Westminster part of London. London is in England. There are 2 places in Westminster where politicians work to make laws. These places are called the House of Commons and the House of Lords.