According to Mary Riddell in The Observer Gordon Brown is thinking of transferring to parliament some or all of the powers currently exercised under the Royal Prerogative:
The reform programme he is hatching will give some prerogative powers of the head of state to Parliament standing above government and the crown. The monarch will be effectively demoted; Brown will be abolishing the divine right of kings.
This is a misunderstanding of royal prerogative powers. They are exercised by the monarch in name only; in practice the royal prerogative gives immense powers to the Prime Minister, whose advice the queen is obliged to accept (other than on a very narrow set of issues). Far from abolishing the divine right of kings, he would be abolishing the unaccountable (and internationally unrivalled) power of the British Prime Minister.
The briefings in the papers today are mainly about the power to declare war. But as I pointed out back in August last year, there are many other powers exercised by the Prime Minister under these powers, with no parliamentary oversight or control, which ought to be transferred to parliament, such as making appointments, granting honors, declaring a state of emergency, signing treaties, issuing passports, deporting foreigners and creating universities.
I predicted last summer that Mr Brown might change this early on if he becomes Prime Minister – but I think it is only likely if he does so right away. Once Prime Ministers grow comfortable exercising these powers, they tend not to be inclined to give them up.