[1][3] Biddulph stood for Parliament at Lichfield at a by-election of 1678,but was defeated in a hard-fought and costly contest.
He voted to fix the price of guineas at 22 shilling in March 1696 and for the attainder of Sir John Fenwick on 25 November 1696.
[5] Biddulph had stood surety for his wife's cousin Morgan Whitley, who had been appointed receiver general of Cheshire and North Wales.
His estates, in which he only held a life interest, were taken over by the Crown, but his time in prison had been detrimental to his health.
Eventually an act of Parliament was passed to allow the Lord Treasurer to compound with him for the debt and the marriage of Biddulph's son provided sufficient funds to cover it.