143 Union Street Newtown was the site of a battle between police and Communists on 19th June 1931. Dozens of people on both sides were injured in the altercation, and 19 men were arested. Around this time hundreds of poor and unemployed people had been forcibly evicted from their homes across Sydney. The Unemployed Workers Movement (UWM) had been attempting to prevent these evictions by squatting and organissing mass turn-outs. Conflict between the activists and police had been escalating, and a battle had already been fought in Bankstown on 17th June 1931. The two-storey house in which the battle took place still stands today, and as late as 2010 bullet holes could still be seen inside the house. The incident inspired a song by Alistair Hulett, “The Siege of Union Street”.

The site was first mentioned in the Sands directory as 105 Union St, until the street numbers changed in 1896. It was probably owned by George Crosby, a butcher, from 1883-1900, who lived next door at 107 (later 145) Union St between these dates and is listed as the ratepayer for the site between 1887 and 1892.