Campaign group Republic has called on all Westminster parties to agree a change to freedom of information laws.  The call comes in light on a protracted legal case between the Guardian and the government over access to Prince Charles's letters to ministers.

Even if the Guardian wins the case all other letters and information about Charles's lobbying of ministers will remain secret.  Only a few letters from nine years ago are covered by the current court case.

Republic's CEO Graham Smith said today:

"It's not good enough to have access only to these letters, the law needs changing so future freedom of information requests stand a chance of success."

"In 2010 all three main parties in Westminster conspired to remove all chance of disclosure of royal secrets.  That decision has to be reversed - the public interest must be put ahead of the interests of the Windsor family."

"The royals are expected to remain above the political fray and keep out of politics.  If Charles or any of his family are breaking those rules the voters have a right to know."

"We can only guess what issues Charles is lobbying on and what impact he has had on government policy.  We shouldn't be left guessing, we have a right to know."

"Given Charles's apparent desire to be a political king this is becoming an urgent issue - the voters must know if Charles is trying to influence government policy, and if he is succeeding."