he was frustrated at the Duke’s unwillingness to pursue Jacobite objectives. After he voted for Hamilton’s motion for deferring a decision on the succession, he was removed from the privy council in December 1704. In 1705, to his annoyance, he was appointed a commissioner for arranging the union with England apparently through the influence of Wharton. Initially he decided not to accept the post, but was persuaded by Jacobite colleagues that it would be useful for him to report back to them on the proceedings. He avoided signing the treaty, and in Parliament became one of the most vigorous opponents of the Union. Although he had some support for the article on communication of trade, he usually voted with the opposition, and abstained from voting on ratification. British parliament and attempt to repeal the Union After the union Lockhart was not one of the but he decided to seek election to Westminster to serve the Jacobite cause, and to distract the ministry from suspicion about the intended invasion. He gave his interest in Lanarkshire to Lord Archibald Hamilton and was returned as Member of Parliament for Edinburgh. He was also returned for Wigtown burghs where he stood as an insurance. In 1713 he took part in an abortive movement aiming at the repeal of the union. He was deeply implicated in the rising of 1715, the preparations for which he assisted at Carnwath and at Dryden, his Edinburgh residence. He was imprisoned in Edinburgh Castle, but probably, through the favour of John Campbell, 2nd Duke of Argyll, he was released without being brought to trial; but his brother Philip was taken prisoner at the Battle of Preston and condemned to be shot, the sentence being executed on 2 December 1715. Lockhart continued to act on behalf of James III; his letters were intercepted by the government in 1727 but he was warned of his imminent arrest by Charles Erskine, a senior government legal officer and managed to escape to the Continent. Argyll's influence was again exerted in Lockhart's behalf, and in 1728 he was permitted to return to Scotland, where he lived in retirement until his death in a duel on 17 December 1731. Writings The "Lockhart Papers" are a significant authority for the history of the Jacobites. Lockhart was the author of Memoirs of the Affairs of Scotland, dealing with the reign of Queen Anne up to the union