That’s a British and Australian expression that means your success is guaranteed.
Wikipeadia says that in 1887, British Prime Minister Robert Gascoyne-Cecil, 3rd Marquess of Salisbury, appointed his nephew Arthur James Balfour as Minister for Ireland. The press had a field day when he referred to the Prime Minister as "Uncle Bob". Balfour later went on to become Prime Minister himself. The theory is that to have "Bob" as one's uncle is a guarantee of success. Alternative expressions include “Robert’s your father’s brother” or “Bob’s your Auntie’s live-in boyfriend”.
General “Gentleman Johnny” Burgoyne obviously had no Uncle Bob. He led his troops south into New York from Montreal in 1777. On the way he enlisted the help of the Native American Indian nation, the Iroquois. The few crossing points on St. Lawrence and the Hudson rivers were obvious strategic choke points, with the two rivers splitting the original colonies in half from Montreal to New York City.
The enthusiastic Iroquois scalped an American farmwife and presented her long red tresses and bloody scalp to Gentleman Johnny, much to his horror and dismay. The American militia began coming out of the woods in great numbers to support the rebel cause as the result of that single unfortunate incident.
At Saratoga, the mufti-clad American hid behind rocks and in trees and slaughtered the British at long range. The English troops were conveniently neatly dressed in parade formation in bright red coats with pretty white lapels. The English never fully adapted to this style of fighting, which was modeled after Indian methods.
The original plan was for Gentleman Johnny to link up with General Howe’s troops, who were suposed to be marching north along the Hudson River from New York City. However, for reasons known only to himself, General Howe changed plans and loaded his 13,000 men into 265 ships in New York harbor and sailed into Chesapeake Bay to capture Philadelphia, the rebel capital. Howe was sucsessful in out-generalling Washington and capturing the city, but it was a clear case of winning a battle and losing a war.
The surrender of Gentleman Johnny at Saratoga involved 6,000 remaining British troops. General Howe also resigned under heavy criticism. The Ambassador to France, Benjamin Franklin, was then able to lure the French into a global conflict, based on the rebel victory.
Rather than an outright unconditional surrender, Gentleman Johnny agreed to allow his men to surrender their weapons, and return to Europe with a pledge not to return to North America. Burgoyne had been most insistent on this point, even suggesting he would try to fight his way back to Canada if it was not agreed. However, the Continental Congress, urged by George Washington, repudiated the treaty and imprisoned the remnants of the army in Massachusetts and Virginia, where they were sometimes maltreated . This was widely seen as revenge for the poor British treatment of American prisoners.
Most of the early victories and guerilla tactics of the Americans can be attributed to the great American General Benedict Arnold. However, in dispatches home, other generals claimed credit for his victories and he was passed over for promotion and then investigated for financial irregularities and corruption by the Continental Congress.
Totally irritated, Arnold switched sides and planned to surrender Fort West Point to the British. However, a courier was captured with the treasonous plans and Arnold escaped and settled in England after receiving a payment from the Crown equivalent to $500,000.
Gentleman Johnny Burgoyne returned to England in disgrace and fathered four illegitimate children. Arnold lived out his life in England and his name is as synonymous in America with treason as Thomas Crapper’s is with the flush toilet.