Saunders was descended from a cadet branch of the Sander family, established at Charlwood in Surrey as early as the fourteenth century. Saunders’ ancestors had settled at Ewell, five miles south-east of Kingston, by the early sixteenth century. His grandfather, having probably sat for Gatton in 1529, was returned for Surrey three times and his father, Nicholas, represented Bletchingley in 1554. Following the accession of Elizabeth, Nicholas remained loyal to the Catholic faith, earning him a brief period of imprisonment in 1578. However, he was a friend of Lord Burghley (Sir William Cecil†),
Saunders was knighted in 1603, and returned for Gatton, about seven miles from Ewell, the following year, either on his own interest or that of the Catholic lord of the manor, William Copley. He presumably had the support of lord admiral Nottingham (Charles Howard†), who had considerable influence in the borough, and under whom Saunders had served on the Cadiz expedition in 1596.
Saunders was named to 95 committees in the 1604-10 Parliament, but is known to have made only two or three speeches. He received 29 committee appointments in the first session, beginning with the committee to consider the grievances set forth by Sir Robert Wroth I on 23 March.
Saunders seems to have taken a close interest in matters to do with the church. Among those instructed on 19 Apr. to prepare for a conference with the Lords about religion, he was appointed to several committees on ecclesiastical affairs, including those against pluralism (4 June), scandalous ministers (12 June) and for the reform of the church courts (16 June).
In June 1605 Saunders wrote to the earl of Salisbury (Robert Cecil†) stating that the lieutenant of the Tower, Sir George Hervey* wanted to resign. He made a request to be his successor but was unsuccessful.
Saunders was named to the committee to consider the bill against purveyance on 30 January.
Saunders was appointed to 13 committees in the third session. On the proposal for the Union, he was among those appointed to attend the conferences with the Lords of 25 Nov. 1606 and 11 June 1607, and was named to the committee to consider the Union articles on 29 November. He sought to reopen the issue of purveyance on 27 Nov. 1606, desiring that ‘there might be a bill thought on and drawn against purveyors and cartakers’, but failed to find a seconder.
Shortly before the opening of the fourth session in early 1610 Saunders joined other Surrey gentlemen in a protest against the project to supply London with water from the much-worked River Wandle. This scheme was designed, in part, for the benefit of Chelsea College, to whom the profits were to be paid.
Saunders played no recorded part in the poorly documented fifth session in late 1610. In February 1611 he wrote to Adam Newton, Prince Henry’s secretary, trying to secure a position in the prince’s Household, but seems to have been unsuccessful.
There is no evidence that Saunders sought election in 1624, when he was presented by Surrey’s Members as a recusant officeholder because ‘his wife is of a popish disposition’. However, Surrey’s representatives also certified that Saunders himself was ‘not suspected any way to be popish’.
Despite being elected on Buckingham’s patronage Saunders showed some signs of independence from the Court. On 5 Apr. he acted as teller, with (Sir) Walter Earle, against adjourning for a week at the king’s request.
On 28 Mar. Saunders was among those added to the committee to consider the bills for naturalizing Samuel Bave, a Gloucester doctor, and Thomas Sotherne, a merchant; he is subsequently known to have attended an undated meeting of the committee.
Despite his experience of the difficulties involved, in 1627 Saunders became involved in a scheme for supplying London with water from Hoddesdon in Hertfordshire.
