Prince Charles asked: ‘are you worried about these letters?’

The letters, known as “black spider memos” in reference to the Prince’s distinctive handwriting, were written to government departments between September 2004 and March 2005.

They were made public, with some redactions, after a lengthy legal battle by Guardian newspaper journalist Rob Evans.

Read extracts from the Prince Charles 'black spider' letters

Despite a 2012 court decision to allow publication, the former attorney general Dominic Grieve vetoed this, saying the letters reflect Prince Charles’ “most deeply held personal views and beliefs.”

That decision was later ruled invalid.

The Prince of Wales was arriving at Marks and Spencer’s Marble Arch shop for an event to mark the Make a Mark youth employability scheme, which is run by the Prince’s Trust.

Accompanying him was Kristina Kyriacou, communications secretary for the Prince and the Duchess of Cornwall. It is Ms Kyriacou who took hold of the microphone as Channel 4 News Political Correspondent Michael Crick attempted to ask the Prince whether he was behaving “unconstitutionally” by writing directly to government ministers.

Clarence House has previously said it is “disappointed the principle of privacy had not been upheld.

“The Make a Mark scheme, which began in 2013, is a training and mentoring initiative in which young people who have previously faced periods of unemployment get work experience. Prince Charles was due to meet young people to give them certificates marking the end of their time on the scheme at the Marble Arch store.

Prince Charles refuses to tell me whether he’s still writing letters to ministers. Video to follow, including aide grabbing my microphone

— Michael Crick (@MichaelLCrick) May 13, 2015