Short answers, pulled from the story.
John Bull was created by John Arbuthnot, a Scottish physician and friend of Jonathan Swift and Alexander Pope. Bull first appeared in Arbuthnot's 1712 pamphlet Law is a Bottomless Pit and was expanded in a four-part political narrative called The History of John Bull, published the same year.
In Arbuthnot's allegory, John Bull personified England and was used to attack the Whigs, their foreign policy, and the financiers profiting from the War of the Spanish Succession. The character brought a fictional lawsuit against figures representing the kings of France and Spain.
John Bull is usually shown as a stout, middle-aged man in a tailcoat, light-coloured breeches, and a low-crowned top hat known as a John Bull topper. By the 20th century his waistcoat typically bore the Union Flag and he was often accompanied by a bulldog.
The satirical artists James Gillray, Thomas Rowlandson, and Isaac Cruikshank developed the standard cartoon image of John Bull from about 1790, depicting him as a stolid, stocky, conservative English country squire in contrast to the French revolutionary Jacobin figure.
Yaqub Sanu, an Egyptian nationalist journalist, depicted John Bull in his underground newspaper Abu-Naddara Zarqa as a coarse, ignorant, drunken bully who stole Egypt's wealth and mangled the French language. This was a pointed contrast to the sympathetic British portrayal of the character.
During the First World War, John Bull's role as a symbol of the common man was largely taken over by the figure of Tommy Atkins. In the interwar period he was replaced as a national personification by Sidney Strube's suburban Little Man, a shift some observers read as reflecting Britain's post-war decline.