The principal methods are questioning government ministers, debating and the investigative work of committees. The government can publicly respond to explain and justify policies and decisions.
MPs and Lords get the opportunity to question government ministers either directly on the floor of the House during the regular oral question times or in writing.
Question time takes place for an hour from 2.35 pm on Mondays, 11.35am on Tuesdays and Wednesdays and 9.35am on Thursdays.
Ministers from each government department attend the Commons on a rota basis to answer oral questions. Each major Government department is allocated to a particular day of the week, with a rota agreed by the Government and Opposition parties.
In the Lords, the House questions government ministers at the start of each day's business, but there are no set days for government departments.
Prime Minister's Questions (PMQs)
The Prime Minister answers questions every sitting Wednesday from 12.00noon -12.30pm.
Debates in the Commons provide an opportunity for MPs to look at the creation and amendment of laws as well as national and international issues and can be on any subject. Votes are often taken to see whether a majority of Members either support or reject any discussed laws or proposals.
Westminster Hall debates take place in the Commons secondary chamber the Grand Committee Room. They give MPs an opportunity to raise local or national issues and receive a response from a government minister.
In the Lords, one day a week is set aside for general debates and short debates take place on most days (lasting one and a half hours). There are no votes on such debates. The House of Lords also check the work of government by scrutinising legislation.
Committees of smaller groups of MPs and/or Lords look at specific policy issues or legislation in detail. Different committees have different roles ranging from offering advice, to producing reports or altering legislation.
The House of Commons has departmental select committees. These were established to 'shadow' government departments and scrutinise the spending, administration and policy of each department.
Both Houses have permanent and temporary committees. MPs and Lords also work together in Joint Select Committees. The government issues responses to most committee reports.