Sharing his father's radical politics, Atherley-Jones became Hon. Secretary of the Westminster Committee which supported William Ewart Gladstone on the question of the Bulgarian atrocities. He was committed to the left-wing of the Liberal Party, although in 1881 he declined an invitation to fight a by-election in Leeds against Herbert Gladstone, son of the Liberal leader. He was chosen as candidate for Ealing in 1884, but as the election approached, had a much better offer from North West Durham which was an area with a large number of miners and where a Liberal victory was much more likely. He was duly selected at the beginning of August 1885 and won the seat with 62% of the vote in the general election in November.