Battalion War Diaries are kept at the National Archives and can usually found in the WO95 series. They give a first-hand account of what the battalion did each day. The diary was written by an officer, often the Adjutant, and although the daily entries are often just a couple of lines long, sometimes a whole page or more can be devoted to a day, perhaps with a copy of the Battalion or Brigade Orders attached to give a wider picture.
Some officers were more diligent in completing the day's diary than others, and some days were busy whilst others were very quiet. This means that the amount of information found for a particular day can very a lot - from a single line to more than a page.
The example below illustrates a fictitious Battalion War Diary and each entry is signed by the completing officer. Officers are usually mentioned by name if they were killed, wounded or posted in or out, but the names of Other Ranks were not usually given.
Sometimes the writing can be a bit difficult to read, but considering the circumstances in which these forms were completed, it can only be expected.