By the influence of his father-in-law he was returned to parliament as one of the members for Sunderland in 1852, and his support of the Liberal Party was rewarded with the recordership of Newcastle in December 1854.
Seymour disputed the fairness of the decision, but he would not publish the evidence, and he was excluded from the bar mess of the Northern Circuit.
He commenced legal proceedings against Mr. Butterworth, the publisher of the Law Magazine, for giving a statement of the case with comments.
His failure to observe this promise was commented on by the Morning Herald, and Seymour sought to institute a criminal prosecution of that paper, which was refused by Lord Campbell.
[1] His views grew gradually more conservative; he contested unsuccessfully Hull in 1857, Southampton in 1865, Nottingham in 1869 and 1870, Stockton in 1880 and South Shields in 1885.