"In the first quarter of 1809, public attention was distracted from the recent British military humiliation in Spain by the scandal of the alleged involvement of the duke of York, the king’s second son and commander-in-chief of the army, in the sale of commissions by his former mistress, Mrs. Mary Anne Clarke. After an open Commons inquiry, its instigator Gwyllym Wardle, radical Member for Okehampton, moved for the duke’s dismissal. His motion was crushed, but the Portland ministry’s resolutions affirming the duke’s innocence were opposed by such a substantial minority that he resigned. The affair prompted popular calls for reform and sparked a series of parliamentary attacks on corruption in high places. Wardle soon fell from grace, and the duke was reinstated in 1811. "
Which demonstrates that it was possible for parliament to tackle high-level (very high-level) corruption( but that it didn't necessarily make a lot of difference) while there was no possibility of anyone making a case publicly against a senior figure in the Napoleonic establishment.