Douglas Fraser: "Why is the Catholic church so good at attracting headlines?"

Gordon Brown last night signalled that he is prepared to consider abolishing the Act of Settlement, which bans Roman Catholics from becoming king or queen and prevents the monarch from marrying a Catholic.

The commitment came during a Commons debate on the UK Government's proposed package on constitutional reform, which coincided with the announcement that Sir Kenneth Calman, Chancellor of Glasgow University, will head the Scottish Constitutional Commission looking into the powers of the Holyrood Parliament 10 years on from the creation of devolution. Its interim report is due by the end of the year.

Among the package of constitutional reforms proposed is one that will require the Prime Minister to secure the approval of MPs before sending troops to war. This would not apply in "emergencies".

All recent attempts to get the 1701 act repealed have failed. In 2001, Tony Blair - now a Catholic - promised to re-examine the 300-year-old piece of legislation but did nothing about it.

Jack Straw, Westminster's Justice Secretary, gave hope to those wanting a change in the law that the Prime Minister could grasp the constitutional nettle and repeal a law which discriminates against one section of society.

MP for Livingston Jim Devine, one of 13 Scottish Labour members who are Catholics, raised the issue during the Commons debate on the White Paper, when he asked the Secretary of State to include it in the abolition of the act, which discriminated against Roman Catholics. He said: "It is legalised sectarianism that has no role in the 21st century."

Mr Straw replied: "Because of the position Her Majesty occupies as head of the Anglican Church, it is rather more complicated than maybe anticipated. But we are certainly ready to consider this. I fully understand that to my honourable friend and many on both sides of the House, it is seen as something which is antiquated."

Last summer, Alex Salmond, the First Minister, after gaining power at Holyrood made a point that he would raise the issue of abolishing the Act of Settlement.

Last night, a spokesman for Mr Salmond said: "There is no doubt that this piece of discrimination has no place in modern society. While Jack Straw's remarks are welcome in indicating that the UK Government is moving in the right direction, it will be important to see what the UK Government will propose. We will be seeking clarification as to what Mr Straw precisely meant."

One of the main stumbling blocks to repealing all parts of the act is that it could in theory mean a Catholic could become head of the Anglican Church.

During the debate, this issue was raised by David Hamilton, Labour MP for Midlothian, who said: "Could I make an alternative point of view and that is not to encourage the Catholic Church to come in nor indeed the Church of Scotland, which is also excluded, but use this (reform) taking us into the 21st century to separate state from church and therefore take churches out of state business."

Mr Straw insisted the Established Church played a "very important role" in the constitution.

At Holyrood, Labour, LibDem and Tory leaders yesterday combined for the announcement that Sir Kenneth Calman is to chair the Scottish Parliament Commission. It is to review devolution powers and publish an interim report later this year.

The former chief medical officer of Scotland and England, ruled out consideration of independence. The SNP stepped up pressure for the pro-devolution parties to produce a plan they can add to the ballot choices in an independence referendum. First Minister Alex Salmond is to set out the next phase of his National Conversation on independence at a speech in Edinburgh today.