Powers of House of Commons and the House of Lords
The House of Commons has, theoretically, a massive amount of formal power.
It has a sovereign legislature, and can make, amend or un-make any law it wishes, and can be only delayed by the House of Lords. Can remove the government of the day in a vote of confidence. E.g. 1979 vote of no confidence in James Callaghan's Labour government.
However, in reality it has only a limited influence over legislation due to executive domination of the House of Commons: the Westminster voting system offers the government majority control over the Commons and the party discipline system allows ministers to control ...view middle of the document...
However, counterbalancing this is a growing trend for landslide majorites, which allows governments to resist pressure from backbenchers and opposition.
The formal powers of the House of Lords are, in contrast, quite unimpressive.
Lords can only delay legislation from the Commons for a year maximum. Cannot delay money-related bills.
Cannot remove the government of the day and can only veto a very limited range of matters like the sacking of senior judges and delay of Westminster elections.
BUT, in practice, the House of Lords often has a greater influence over the government than the Commons. E.g. Tony Blair's government was never defeated in the Commons but had 353 defeats in the Lords.
Much weaker party system in the Lords than the Commons. Since peers aren't elected, they cannot be made to 'toe the party line', or follow party discipline. What's more, many peers are cross-benchers, who don't have any party ties at all.
There is no party majority in the Lords, so no party holds control over the house.
Since the removal of hereditary peers, the House of Lords has become more assertive and keen to check the government of the day. Peers no longer feel that the chamber is tainted by the predominance of the outdated and irrational hereditary principle. Some peers feel it's their job to compensate for the ineffectiveness of the House of Commons.
Although acts of parliament have made the Lords formally subordinate to the Commons, governments are often keen to look for a compromise rather than invoke the Lords and end up in long term 'parliamentary ping pong'.