It was revealed last week that Prince Charles has met frequently with Cabinet ministers since 2010, prompting allegations that the first in line to the throne had purposefully been "lobbying" the government.
“His Royal Highness receives Ministers and officials from a broad range of Government departments on a regular basis," Clarence House said in a statement about the prince's meetings.
“The Prince of Wales has a right, indeed it is his duty, to communicate privately with the Government on any matter he chooses, to bring his unique perspective and reflect the many issues people raise with him personally on his extensive engagements around the country."
On Sunday, however, the duke of Cornwall's public relations crisis deepened, when word broke that he had sent three members of his staff to work in two government departments -- the Cabinet Office and the Department of Environment, Food and Rural Affairs.
Several ministers said they were unaware of the appointments and claimed that the prince had overstepped the bounds of the monarchy.
"Planting his civil service moles proves [an] intention to abandon royal political neutrality," Labour MP Paul Flynn said.
"It raises constitutional questions about the influence the monarch-in-waiting has over policy and there will be questions in the house when it returns," Labour MP Paul Farrelly said.
Clarence House confirmed the appointments as a means for junior staff to gain experience, but denied that the prince had used his employees to further his interests in government.
Flynn, who plans to bring the issue to the House of Commons' reform committee, told the Independent that Charles' "main qualification for the job is that he doesn’t get involved in politics.”
"We now have this extraordinary story that he put his minions in two departments. Few things really surprise me, but I’m astonished by this," he said.