I am afraid it is a derelict building full pigeons
This is Monks Park. It was so known from the mid-thirties when the surrounding housing estate was born. I believe if you were to cross the Harrow Road, you would find yourself in 'Tokyngton'. Monks Park road travels from the Harrow road alongside 'Monks Park' to where the park terminates, mainly because of the railway from what is now the 'stadium' to Marylebone station. On either side of the river, land was left vacant as an overflow for the river. Some houses were hit during the war, and when they were rebuilt, their ground floors were re-built to allow the floodwaters to pass unnoticed under the floorboards. It is certainly true of 18-20 monks park(road).