John Lambert, also spelt 'Lambart' was an English Parliamentarian general and politician. Widely regarded as one of the most talented soldiers of the period, he fought throughout the Wars of the Three Kingdoms, and was largely responsible for victory in the 1650 to 1651 Scottish campaign.
Although involved in the discussions between the New Model Army and Parliament during 1647, his first formal involvement in civilian politics was in 1653 when he became a member of the English Council of State. In December 1653, he helped prepare the 'Instrument of Government', which provided the constitutional framework for the Protectorate. He later fell out with Oliver Cromwell, largely because he opposed converting his role as Lord Protector into a kingship.
He lost his offices in 1657 after refusing to swear an oath of loyalty to Cromwell, and after Cromwell's death in September 1658, he re-entered politics as Member of Parliament for Pontefract in early 1659. When Richard Cromwell resigned in May, he became a member of the Committee of Safety and successfully suppressed the Royalist Booth's Uprising.