The task was enormous, and made particularly difficult due to the nature of air operations where an aircraft might be lost at any point from take off to landing back at base.

During the war years, investigation of missing aircraft and crews was hampered because of the difficulty in obtaining information from overseas in occupied countries. The investigations were carried out from an office in London and relied on information received from the International Red Cross telegrams, reports from France, Holland and Norway forwarded by the Red Cross, reports from Allied agents in enemy or enemy occupied territory as well as reports from Air Attaches and others in neutral countries. A list issued by Germany, the Totenliste, also helped by supplying additional details such as place of burial in some cases. They did not, however, include the details about where the aircraft had crashed.

Using these scraps of information, together with known details about which aircraft and crews had been reported missing, investigators could begin to build a picture as to the fate of some of the missing airmen.

After D-Day and the liberation of parts of Europe, it was possible to make fuller investigations. Now it was possible to receive reports directly from the areas where the aircraft had crashed. Some captured German records helped, as did the many relics and personal effects that had been rescued from the scene by the people of occupied countries who had then hidden them from the Germans during the period of occupation.

Identification of airmen who had died was assisted by the smallest of details such as a laundry mark on an item of clothing, the serial number on a service watch or the initials on a signet ring. It was painstaking and often harrowing work.

In November 1944, the Head of the Casualty Branch and the Officer in Charge of Missing Research went to Paris, and during their visit it became apparent that there was a need for a single unit or branch to undertake and co-ordinate the work of investigating the many airmen who were missing. Consequently, in early 1945, The Royal Air Force Missing Research and Enquiry Service was founded.

Working initially in France, Search Officers were despatched to the places where aircraft were believed to have crashed. Their work involved interviewing local Mayors and their employees, local police, and anyone else likely to have information that would help.

To begin with, the Casualty Branch sent Casualty Enquiry forms, detailing all known information to date about a particular aircraft and crew. The Search Officers worked with this information, adding to it where possible before writing a report to send back to London. Once all the facts and the burial place were known the MRES arranged for the Graves Registration Directorate to register and mark the grave. When this was completed a case would be considered closed.

Eventually it was realised that due to the number of crashes to be investigated a more methodical approach to locating and investigating them would be required. After dealing with the Casualty Enquires from London, Search Officers would then search in their area village by village and district by district.

In April 1945, a second Section was set up in Brussels. Eventually, sections were also established in Holland, Denmark, Norway, Italy and Germany. Searches were conducted in each of the countries by Officers working firstly from the Casualty Enquiries and thereafter by covering the country village by village, district by district.

With the increasing volume of enquiries as the MRES moved their searches into more and more countries; there was a requirement to recruit more Search Officers. Therefore, in August 1945, the Air Ministry sent a letter to three camps in England, Church Fenton, Wittering and West Malling, which were re-settlement centres for Ex-Prisoners of War. Without mentioning the type of work to be undertaken, they asked for volunteers to work overseas.

Those who volunteered then reported to the Air Ministry Casualty Branch to be interviewed for selection. During their selection interview they were told the type of work that they would be required to do if selected. The volunteers then returned to their centres to await the decision of the Air Ministry.

Volunteers selected after this interview were then asked to return to the Air Ministry Casualty Branch to attend two days of lectures regarding the type of work that they were to undertake with the MRES. After being given time to arrange any personal matters in the UK, they reported to St James House in London on August 30th and were flown overseas to complete their training in the field.

After spending around a week in the field accompanying existing experienced Search Officers, they joined a Section. The Sections generally comprised a Commanding Officer and Six Search Officers. These Officers then commenced their own investigations in the countries that they were despatched to with their Section.