The Irish Guards were an Infantry Battalion that would have had an MG Section as part of its Battalion Headquarters. These weapons would have been brigaded when the Machine Gun Corps was formed in 1915. The guns, and crews, would have been formed into a Machine Gun Company.
During the Great War, the dispositions of Battalions were as follows:
The 1st Battalion was part of the 1st Guards Brigade, Guards Division. It's MG Section was transferred between 01 September and 19 September, 1915, to form the 1st Guards Bde. MG Coy..
The 2nd Battalion joined, from England on 19 August, 1915, the 2nd Guards Brigade, Guards Division. It's MG Section was transferred between 01 September and 19 September, 1915, to form the 2nd Guards Bde. MG Coy.
In 1922, the Machine Gun Corps and Guards MG Regiment were disbanded and the guns returned to the Infantry Battalion as a Machine Gun Platoon and then formed as a Machine Gun Company in the early 1930s.
This remained until the formation of Divisional Machine Gun Battalions in 1936 where guns were brigaded once again.
After the Second World War, the MG assets reverted to MG Platoons within support companies of Infantry Battalions.