On Thursday MPs used the Parliament Act to push through a ban on fox and deer hunting and hare-coursing with dogs from February 2005.
The little-used act - sometimes described as Parliament's "nuclear deterrent" - is invoked when MPs and peers cannot agree on a Bill.
Once this happens, the Bill may be passed in the next Parliamentary Session without the consent of the House of Lords under section 2 of the Parliament Act 1911, as amended by the Parliament Act 1949.
The pro-hunt Countryside Alliance wants to challenge the legitimacy of the 1949 Parliament Act, which was never passed by the House of Lords.
The 1911 Act was introduced by the Liberal Prime Minister, Herbert Asquith, after Conservatives defied centuries of parliamentary precedent and used their majority in the Lords to block Lloyd George's "people's Budget" of 1909.
The Act - which was approved by both the Commons and the Lords - restricted the powers of the House of Lords to delay and block legislation.
Peers would only be able to reject a Bill for two years over three successive parliamentary sessions.
USE OF THE 1949 PARLIAMENT ACT
1991: War Crimes Act
1999: European Parliamentary Elections Act
2000: Sexual Offences Amendment Act
2004 Hunting Bill
After that it could become law in spite of their objections.
New restrictions on the powers of the Lords were introduced in the 1949 Parliament Act which reduced the time peers could delay a bill from two years over three parliamentary sessions to one year over two parliamentary sessions.
But Clement Attlee's Labour government had to use the 1911 Act to get the Bill onto the statute book.
Ever since constitutional lawyers have debated whether the 1949 Act - and therefore any law introduced as a result of the Parliament Acts - is valid.
The issue has never been tested in the courts - something the Countryside Alliance hopes to change when it applies for a judicial review on Friday.
It believes that for the government to use legitimately the Parliament Act the Bill needs to have been rejected by peers three times not twice.
But the government has said it is confident of seeing off any legal challenges.