British History Online, about the acquisition of the site for London's County Hall, gives "Gilbert was one of two brothers who were LCC Members at the same time but sat on opposite sides. J. D. was a Progressive and an agnostic, the other, John, was a Municipal Reformer and an ardent Roman Catholic. It is said that they never spoke to each other."
James Daniel Gilbert was born and brought up in West Newington. Became a Liberal politician, banker and City merchant. Represented West Newington/Southwark Central in the LCC 1898-1928. During this time he was chair of a number of committees including one responsible for the Fire Brigade. Early proponent for the new County Hall building to be erected on the site that was eventually chosen.
His brother (Sir John William Gilbert, 1871 – 1934) was also a member of the London County Council but represented a different, less progressive, party. Their religious views were also diametrically opposed and it is said they never spoke to each other.
He was an MP for the same area, 1919 - 24. Died in Stourbridge, Worcestershire.