Sanderson came from an old south Yorkshire family, but little is known of his antecedents. His father may have been the son of John and Margaret Sanderson who was baptized at Armthorpe on 16 Apr. 1751. His parents married at Doncaster on 27 June 1775 and his brother Thomas was baptized at Armthorpe on 13 June 1779.
Sanderson, by now a very wealthy man, was taken up by the anti-Catholic and Tory corporation of Colchester in April 1829 to replace their member Sir George Smyth when he resigned his seat in disgust at the Wellington ministry’s concession of Catholic emancipation. He was returned after a token challenge had come to nothing, and declared that he wished to promote ‘the education of the poor’ and help to ‘put an end to the traffic in human blood’.
Sanderson offered for Colchester at the general election the following month but he had to withdraw at the last minute when one of his agents was detected in an act of bribery.
the necessity of parliamentary reform ... Approving ... much of the [Grey ministry’s reform bill] ... I doubt the ... necessity of some of its provisions. Agreeing in the extension of the franchise to large and populous places, yet I cannot see the wisdom and justice of seizing on the property and charters of unoffending towns and depriving them of their rights.
While he polled very respectably, he finished third.
