The Club House resumed normal activities in the second half of 1915 after hosting Belgian refugees during the early part of the war. Normal service did not last for long. By February 1916 it had been adapted for a new full time role -
The Club House became the Garden Suburb Auxiliary Military Hospital (AMH) in February 1916 (it served as an annexe of the Hampstead Central Military in Mount Vernon). Over 3,000 AMHs were established during the Great War. Between 1916-19, the Garden Suburb AMH treated 1,700 patients. There were no mortalities, largely because most of its patients were ambulant and convalescent.
Suburb residents contributed time and money towards the establishment and upkeep of the AMH. Beds were sponsored at £5 a time, food was donated, money was given and appeals were made for items required by patients. Medical supervision and treatment was provided by an Officer-in-Charge and by a roster of GPs and specialists. Nursing and general care was provided by the Middlesex/40 Voluntary Aid Detachment.