In 1907 Chairman and Managing Director of the White Star Line, Joseph Bruce Ismay and his wife Florence arrived for dinner at the Belgrave Square home of Lord Pirrie and his wife Margaret. William James Pirrie was managing director of the Harland & Wolff shipyard in Belfast. Ismay was the Managing Director of the White Star Line, one of Britain's most pre-eminent shipping companies, and since 1902 part of the International Mercantile Marine.
Standing on the south west corner of Belgrave Square in London the house is a Greco- Roman style mansion built in around 1840. Designed by London architect Henry Edward Kendall (1776-1875), the house features a central three-storey block, five bays wide with two-storey three-bay wings either side. The house is rendered in stucco and is painted white.
That night, plans were drawn up for a new class of transatlantic liner, operating a two-liner express service to New York. The liners were to be far larger and more luxurious than any vessel in service at the time. They were to be a third as large again as the new Cunarder Lusitania and Mauretania, and would exceed eight hundred feet in length.
Horsepower would be a moderate 45,000 horsepower produced by a reciprocating/turbine engine configuration providing economical fuel costs and a respectable service speed of 21 knots. The vessels would bear the names Olympic and Titanic.
The ground floor has a large, projecting porch with a plain pediment, supported by four pairs of Gothic-style columns. Above, the windows of central three bays are set between Corinthian-style pilasters, set beneath a plain pediment with a central tympanum. Above, the windows have a plainer architrave.
The central block has rusticated corners, while at ground floor level the facade has horizontal banded rustication. The roof of the central block of the house is finished with a balustraded parapet, while that of the wings has a plain entablature and parapet.
The house was first listed on 24 February 1958 and currently has Grade I-listed status, the most significant listed status. Additional the gate posts, piers and spearheaded-railings were listed on 9 January 1970 and currently have Grade II*-listed status.
Today, no 24 Belgrave Square, formerly known as Downshire House, serves as the London home of the Spanish embassy; historically Downshire House is recognised as a significant landmark, as the place where the story of the Titanic began.