The monarch may refuse to give royal assent to a bill, which would prevent it from becoming law. However, this power is now largely theoretical, as the monarch has not refused royal assent to a bill since the 18th century.
2. Parliament's control over taxation and expenditure
The monarch cannot raise taxes or spend money without the consent of Parliament. This means that Parliament has the power to control the monarch's finances, and thus to limit the monarch's power.
3. The right of Parliament to impeach the monarch
Parliament has the power to impeach the monarch, which would result in the monarch being removed from office. This power has only been used once in British history, when Parliament impeached Charles I in 1649.