These four brigades were formed as part of the raising of the First New Army, K1. They are also sometimes shown as 46 to 49 (Howitzer) Brigades RFA.
XLVI
- This brigade was originally comprised of numbers 148, 149 and 150 Batteries RFA and the Brigade Ammunition Column. It was placed under command of the 14th (Light) Division and went to France with it in May 1915.
- On 14 January 1915 the three six-gun batteries were reorganised to become four four-gun batteries and were titled as A, B, C and D.
- On 24 May 1916 D Battery left to join 49 Brigade of the same Division, being replaced by the former C (Howitzer) Battery of that brigade which now became D/46.
- On 5 October 1916, A, B and C Batteries all increased to six guns when joined by sections from 49 Brigade. The same happened to D Battery on 8 January 1917 when a section joined from 48 Brigade.
XLVII
- This brigade was originally comprised of numbers 151, 152 and 153 Batteries RFA and the Brigade Ammunition Column. It was placed under command of the 14th (Light) Division and went to France with it in May 1915.
- On 14 January 1915 the three six-gun batteries were reorganised to become four four-gun batteries and were titled as A, B, C and D.
- On 24 May 1916 D Battery left to join 49 Brigade of the same Division, being replaced by the former B (Howitzer) Battery of that brigade which now became D/47.
- On 6 October 1916, A, B and C Batteries all increased to six guns when joined by sections from 49 Brigade. The same happened to D Battery on 8 January 1917 when a section joined from 48 Brigade.
XLVIII
- This brigade was originally comprised of numbers 154, 155 and 156 Batteries RFA and the Brigade Ammunition Column. It was placed under command of the 14th (Light) Division and went to France with it in May 1915.
- On 14 January 1915 the three six-gun batteries were reorganised to become four four-gun batteries and were titled as A, B, C and D.
- On 24 May 1916 D Battery left to join 49 Brigade of the same Division, being replaced by the former D (Howitzer) Battery of that brigade which now became D/48.
- On 1 October 1916 C Battery was broken up, with sections going to A and B Batteries to bring them up to six guns each.
- 528 Howitzer Battery joined and was renamed as a new C (Howitzer) Battery on 26 October 1916.
- The brigade left the Division on 7 January 1917 and was converted into an Army Brigade RFA.
- At the same time, C Battery was broken up, with sections going to 46 and 47 Brigades. A Battery of 158 Brigade joined and was renamed as C/48.
- A section joined D Battery from D Battery of 293 Brigade on 16 February 1917.
XLIX (Howitzer)
- This brigade was originally comprised of numbers 157, 158 and 159 (Howitzer) Batteries RFA and the Brigade Ammunition Column. It was placed under command of the 14th (Light) Division and went to France with it in May 1915.
- On 14 January 1915 the three six-gun batteries were reorganised to become four four-gun batteries and were titled as A, B, C and D.
- On 17 June 1915 A Battery was sent to be attached to 28th Division and it moved permanently to that formation on 3 September 1915, becoming A Battery of 130 (Howitzer) Brigade.
- On 24 May 1916 B Battery left and became D Battery of 47 Brigade. C Battery also left and became D Battery of 46 Brigade, and D left to become D Battery of 48 Brigade.
- On the same day, the D Batteries of 46, 47 and 48 Brigades all joined and became A, B and C Batteries.
- The brigade was broken up on 5-6 October 1916, with sections of batteries going to 46 and 47 Brigades.