Catholic Online reports that the move challenges more than 300 years of state-sponsored sectarian discrimination and bigotry against Catholics.
Liberal Democrat equality spokesperson Lorely Burt announced on 23 May that the party has introduced in the House of Commons the "Discrimination Against Catholics" motion that takes aim sections in the Bill of Rights 1688, Act of Settlement 1700 and the Union with Scotland Act 1706 which prevent a "monarch from being a Catholic and the spouse of the monarch from being a Catholic".
"There is a fundamental principle of discrimination here," said Burt, Independent Catholic News reports.
"It is unacceptable that in 2007 we still have ridiculous laws on our statute books that, for example, prevent a Catholic from marrying the heir to the throne."
Burt called upon British Prime Minister Tony Blair to "consider removing this institutional discrimination" before stepping down on June 27.
"After all," Burt said, "if reports are to believed, he may have a rather more personal interest in Catholic affairs when he leaves Number 10" Downing St, the residence and office of the prime minister, referring to rumours of Blair's imminent conversion to Catholicism.
"He should act whilst he still has the chance."
Last year, a Scottish cardinal launched an attack on the 300-year-old Act of Settlement, decrying "state-sponsored sectarian discrimination" which leaves a blight on the cultural landscape.
Cardinal Keith O'Brien of St Andrews and Edinburgh said Scotland remains afflicted by a "shadowy sectarian culture".
Opponents of repeal believe that repeal could lead to a Catholic assuming the throne, and could lead to the disestablishment of the Church of England as the state religion, as the English monarch must swear to defend the faith and be a member of the Anglican Communion.
Earlier in 2006, Blair rejected calls for repeal.
British Cardinal Cormac Murphy O'Connor of Westminster urged repeal of the law in June 2002.
The Act of Settlement, he said, "is not so much that it is an act of discrimination against Roman Catholics - which it is - but it seems to me to be discrimination against the royal family."
"Talking about Prince William, he can marry by law a Hindu, a Buddhist, anyone, but not a Roman Catholic," he said. "That seems to me anomalous and I think it should go."
British party calls for end of 300-year-old discriminatory law against nationâ€™s Catholics (Catholic Online, 26/5/07)
LINKS (not necessarily endorsed by Church Resources)
British monarchy (Wikipedia)
Time we can have a Catholic monarch, says new Ireland Anglican primate (CathNews, 19/1/07)
Royal Family member to wed at Vatican (CathNews, 1/11/07)
Catholic congratulations for Queen on 80th birthday (CathNews, 26/4/06)
British Cardinal makes history preaching to Queen (CathNews, 14/1/02)
Call for Queen to lose title as head of Church (CathNews, 16/6/03)