The story of successive governments' attempts to reform the Lords goes to the heart of the debate about democracy: how do we decide what is the will of the people - and who stands up for minority interests?
The Lords can trace its origins back to the fourteenth century, when royal advisers began to divide themselves into commoners and lords.
By the end of the nineteenth century, Britain was becoming a constitutional democracy, but the Lords had failed to keep pace with those changes. Reforming the Lords was considered numerous times, but with limited practical results.
Its main functions are:
A "second pair of eyes" on bills which have already been debated in the Commons. The Lords makes around 2,000 amendments a year to legislation, nearly all of which are accepted.
Regular Question Times for government ministers in the Lords.
Through specialist select committees, such as Science and Technology.
Increasingly, the Lords initiates legislation, which is debated by the Commons.
The Lords is the final court of Appeal in Great Britain. In practice, this is done by specialist Law Lords, who are chosen from the judiciary.