the period between 1538 and 1558). From 1540 to 1545 he was Master Forester for Quernmore and Wyresdale in Lonsdale Hundred. These were lucrative appointments that gave him a wide range of useful contacts. Siege of Haddington In the reign of Edward VI of England, Holcroft was given still more power and responsibility. During 1548–9 he headed the English spy network in Scotland and spent more than £400 of his own money on the work. The English commander Grey de Wilton, wrote to Edward Seymour, 1st Duke of Somerset, "rejoicing in the diligence, good will, and courage of the Lord Warden and Mr. Holcroft." Holcroft won great distinction during the Siege of Haddington. The English garrison at Haddington held out against a Scottish and French army. Thomas Fisher, charged with arranging the return of Mary, Queen of Scots, to marry Edward VI, wrote of Haddington in a letter to William Cecil: "I assure you it had been French ere this, but for Master Holcroft, who has served as few men living would and with such liberality as is wonderful". Edward VI heard about the exploits of Holcroft and Thomas Palmer bringing food to the besieged garrison at Haddington, and recorded their names in his journal. Holcroft and Francis Leek wrote from Alnwick to Edward Seymour, now Duke of Somerset, in January 1549, about constructing further fortifications at Haddington, Lauder, and Lindisfarne. Fall of Somerset Holcroft became close to Somerset and chief regent of the young Edward VI, and to William Paget, Seymour's key administrator. Seymour was closely identified with the partly successful Scottish campaigns and Holcroft was given an annuity of £100 "until better provided for" when the wars ended. Seymour was toppled from power in October 1549 but later released from imprisonment and allowed to resume his place on the council. During this period Holcroft visited Paget's homes a total of nine times. The final downfall of Somerset in October 1551 brought the arrest of both Paget and Holcroft. He was imprisoned in the Tower until June 1552. He was also forced temporarily to surrender his office as receiver of the Duchy of Lancaster. However, he escaped with his head and was able to resume his activities after his release. In Mary's reign, Holcroft, like Paget and many other Somerset supporters, was back in favour. He was made Knight Marshal, a senior post in the household he held from