A documentary for Channel 4 has claimed King Edward VIII was subject to phone-tapping surveillance during the 1930s, due to fears he might have been a Nazi sympathiser.
Uncovered: Spying on the Royals claims Government ministers were afraid the king might have been a "stooge" for Nazi Germany because of potential leanings towards fascism.
It claims a secret unit of MI5 tapped the king's phone around the time he began a relationship with American divorcee Wallis Simpson out of fears he might have been discussing secret intelligence reports with her.
The documentary says that his father, George V, who was on his deathbed, advised then-Prime Minister Stanley Baldwin to have Edward monitored in an unprecendented move.
At that point, no member of the royal family had been watched by security services before.
The conversations revealed the young king was willing to give up "crown and country" for Simpson. This is something he would eventually follow through with, abdicating to marry his American lover.
This caused a major constitutional crisis until Edward was succeeded by George VI - the father of current ruler Elizabeth II.
The Royal press office declined to comment on the story.