The motion, put down by Scottish National Party MSP Mike Russell, says the discrimination contained in the act has no place in modern society.

As many as 66 MSPs have now signed the motion - including most of the SNP group, most of the Tories including their leader David McLetchie, the three Independents and several Lib Dem and Labour MSPs.

The motion calls for the repeal of the discrimination enshrined in the Act of Settlement and says that Scottish society must not disbar participation in any aspect of national life on the grounds of religion.

Mike Russell: "Message to Tony Blair"

The motion will not be debated, although the SNP is now likely to bring forward a similar motion opposing religious discrimination and force a vote.

Mr Russell said this motion would send a strong signal to the prime minister that the Scottish Parliament wants the law changed.

Pressure has been growing for the repeal of the law which prevents a Catholic ascending the throne, and forbids the heir to the throne marrying a Catholic.

Roseanna Cunningham, the SNP MP and MSP for Perth, has tabled a House of Commons motion calling for the reform of the 18th Century law.

Former Solicitor General and Lord Advocate, Lord Fraser of Carmyllie, and former Scottish Secretary Lord Forsyth of Drumlean, have also pledged to present a bill in the new session of Parliament.