Tranby Croft scandal, 1890  

The Tranby Croft affair was a minor scandal in King Edward's life. Tranby Croft was the home of Arthur Wilson, a shipbuilder. In September 1890 Prince Edward and his friends were his guests, and the evenings were spent playing baccarat. One guest, Sir William Gordon-Cumming, was seen cheating. Edward was told and he exacted a signed agreement from Gordon-Cumming; in exchange for the silence of all present, Gordon-Cumming would never play cards again.

By the next year, the word had gotten out, and Gordon-Cummings attempted to clear his name by bringing a civil action against Edward's friends who had made the accusation. In June 1891, the case was heard before the Lord Chief Justice, and Edward was subpoenaed as a witness.

Although Edward was not on trial, Gordon-Cummings' solicitor was merciless and insulting in his cross-examination, especially about Edward's personal life, and the public perception began to form that Edward had done something horribly unlawful at Tranby Croft. Rumors also spread that Gordon-Cummings had "taken the fall" for Edward. (This was fueled, in part, by the perception of baccarat being a "foreign" card game.) Flashman's remark that he personally kept Edward out of trouble must be taken with a grain of salt. 

Sources:

From Flashman and the Tiger:

"Hadn't I plucked him [Bertie] untarnished, more or less, out of the Tranby card scandal only three years earlier?"

From Flashman in the Great Game, page 9

"and after I had ridden herd on that same precious Teddy through the Tranby Croft affair..."

Source:

Pearson, John. Edward the Rake: An Unwholesome Biography of Edward VI, Harcourt Brace Jovanovich, New York, 1975.