Part of the first batch of Argus to arrive in the UK. The Air Ministry was unaware that the British Purchasing Commission had already allocated a serial in the EV block and gave it a new serial HM181. It was decided it and the small number of other aircraft affected should keep their new serials. The rest of the batch received BPC-allocated EV serials. HM181 was delivered to the Air Transport Auxiliary. Photo from: Imperial War Museums