Letters from soldiers on active service were subjected to censorship by their junior officers to ensure that details such as location and military objectives were not disclosed. However, as a privilege, soldiers were given one green envelope per month in which they could send uncensored personal and private letters to loved ones.
Field Service Postcards were used by soldiers on active service to send speedy messages home without any need for censoring by their officers. Their purpose was to reassure their loved ones that they were alive and well and to confirm that letters and parcels from home were getting through to the Front. The soldier was allowed to delete as appropriate from a selection of pre-printed sentences. If anything other than a date and signature were added the card would be destroyed.