On 15 August 1914, the War Office issued instructions to separate those men who had signed up for Home Service only, and form these into reserve units.

[2] The 207th (2nd Essex) Brigade was constituted as follows:[2] By December 1914 the East Anglian Reserve Division concentrated around Thetford in Norfolk in early 1915.

Training was impeded by the lack of arms and equipment and the constant drain of providing drafts to the 1st-Line battalions (the 1st East Midland Brigade was serving at Gallipoli).

The division and brigades thereby lost their local associations, and titles like 'East Anglian' and 'East Midlands' were dropped from 1 January 1918.

[2] At the end of the winter, 206 Bde moved to Thoresby Hall, later returning to Clipston, and remained a training formation for the rest of the war.