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Political career

Walpole's political career began in January 1701 when he won a seat in the English general election at Castle Rising in Norfolk. He left Castle Rising in 1702 so that he could represent the neighbouring borough of King's Lynn, a pocket borough that would re-elect him for the remainder of his political career. Voters and politicians nicknamed him "Robin".

Like his father, Robert Walpole was a member of the Whig Party. In 1705, Walpole was appointed by Queen Anne to be a member of the council for her husband, Prince George of Denmark, Lord High Admiral. After having been singled out in a struggle between the Whigs and the government, Walpole became the intermediary for reconciling the government to the Whig leaders. His abilities were recognised by Lord Godolphin (the Lord High Treasurer and leader of the Cabinet) and he was subsequently appointed to the position of Secretary at War in 1708; for a short period of time in 1710 he also simultaneously held the post of Treasurer of the Navy.

Despite his personal clout, however, Walpole could not stop Lord Godolphin and the Whigs from pressing for the prosecution of Henry Sacheverell, a minister who preached anti-Whig sermons. The trial was extremely unpopular with much of the country, causing the Sacheverell riots, and was followed by the downfall of the Duke of Marlborough and the Whig Party in the general election of 1710. The new ministry, under the leadership of the Tory Robert Harley, removed Walpole from his office of Secretary at War but he remained Treasurer of the Navy until 2 January 1711. Harley had first attempted to entice him and then threatened him to join the Tories, but Walpole rejected the offers, instead becoming one of the most outspoken members of the Whig Opposition. He effectively defended Lord Godolphin against Tory attacks in parliamentary debate, as well as in the press.

In 1712, Walpole was accused of venality and corruption in the matter of two forage contracts for Scotland. Although it was proven that he had retained none of the money, Walpole was pronounced "guilty of a high breach of trust and notorious corruption". He was impeached by the House of Commons and found guilty by the House of Lords; he was then imprisoned in the Tower of London for six months and expelled from Parliament. While in the Tower he was regarded as a political martyr, and visited by all the Whig leaders. After he was released, Walpole wrote and published anonymous pamphlets attacking the Harley ministry and assisted Sir Richard Steele in crafting political pamphlets. Walpole was re-elected for King's Lynn in 1713.