London, May 13 (IANS): Prince Charles's secret letters written to British government ministers a decade ago will now be published on Wednesday, The Guardian reported.

The move follows a 10-year battle by The Guardian newspaper to expose the heir to the throne's so-called 'black spider memos' to public scrutiny.

The 27 letters were sent by Charles to ministers in seven government departments between 2004 and 2005.

The government has been battling to protect the Prince of Wales from scrutiny over what former attorney general Dominic Grieve has described as Charles's "particularly frank" interventions on public policy in the letters.

Grieve vetoed the information tribunal's original decision to order publication in 2012, warning that the letters "contain remarks about public affairs, (which) if revealed, will have a material effect upon the willingness of the government to engage in correspondence with the Prince of Wales, and would potentially have undermined his position of political neutrality".

In March, supreme court judges finally approved the publication of the letters. Prime Minister David Cameron said at the time that the decision was "deeply disappointing".