In 1901 Guernsey passed a law confirming that service was compulsory, unless exempted, with an upper age of 60 in time of war and 45 in time of peace.
10 years active service, with an establishment of 1,000 during peace and 2,000 in time of war, comprising one artillery regiment, two of infantry and two infantry reserves.
The law also confirmed the Army Act 1881 applied to the Island.
In 1901 it was reported that any man in Guernsey, when called upon, was bound by law to attend with pay 21 days of training with the Militia until he was declared efficient this training took place during the month of August any man failing to make the grade had to return the following year until he qualified.

In February 1906 militiamen became eligible for the Militia Long Service Medal.
The medal was awarded for 18 years of efficient and irreproachable service in the Militia and attending 15 annual camps.

The Royal Guernsey Militia, comprising two infantry regiments and an artillery regiment, could not fight as a unit outside the island except to help the King regain his throne.
Accordingly, the militia was disbanded in 1916 to allow the Royal Guernsey Light Infantry to be raised, the Island waiving its rights and allowing the first battalion of the regiment to serve overseas and introducing conscription.
A second (reserve) battalion remaining in Guernsey.
Casualties in France were high.
327 died, 667 wounded and 255 became prisoners.
The severely depleted regiment becoming GHQ troops guarding General Haig from April 1918.

From 1920 Royal Guernsey Militia and Royal Alderney Artillery Militia British army numbers were in the block 7539001 – 7560000 (Use of the numbers were discontinued in 1929).
Reinstated after World War I in 1922, the militia was scaled back in 1929, following a reduction in funding, to a small volunteer force.

The militia was demilitarised in 1940, with all equipment being shipped to England just before the invasion of Guernsey by German forces.

One former member of the militia, Lt.
Hubert Nicholle who had travelled to England in 1939 to join the Hampshire Regiment agreed to travel back to Guernsey by the British submarine H43 where on 7 July 1940 he undertook a successful reconnaissance of German defences in the Island during the lead up to Operation Ambassador, before being picked up on 10 July.
Undertaking a second landing with fellow Guernseyman Lt.
James Symes on 3 September 1940, in civilian clothing,  the pickup arrangements failed and the two were forced to surrender, after having obtained help from Ambrose Sherwill to get Guernsey Militia uniforms, being treated as POWs rather than shot as spies.
Nicholle was awarded the MC.

The militia was reconstituted after the war, however in 1951 the States of Guernsey finally decided not to revive the militia.
In 1901 Guernsey passed a law confirming that service was compulsory, unless exempted, with an upper age of 60 in time of war and 45 in time of peace. 10 years active service, with an establishment of 1,000 during peace and 2,000 in time of war, comprising one artillery regiment, two of infantry and two infantry reserves. The law also confirmed the Army Act 1881 applied to the Island. In 1901 it was reported that any man in Guernsey, when called upon, was bound by law to attend with pay 21 days of training with the Militia until he was declared efficient this training took place during the month of August any man failing to make the grade had to return the following year until he qualified.
In February 1906 militiamen became eligible for the Militia Long Service Medal. The medal was awarded for 18 years of efficient and irreproachable service in the Militia and attending 15 annual camps.
The Royal Guernsey Militia, comprising two infantry regiments and an artillery regiment, could not fight as a unit outside the island except to help the King regain his throne. Accordingly, the militia was disbanded in 1916 to allow the Royal Guernsey Light Infantry to be raised, the Island waiving its rights and allowing the first battalion of the regiment to serve overseas and introducing conscription. A second (reserve) battalion remaining in Guernsey. Casualties in France were high. 327 died, 667 wounded and 255 became prisoners. The severely depleted regiment becoming GHQ troops guarding General Haig from April 1918.
From 1920 Royal Guernsey Militia and Royal Alderney Artillery Militia British army numbers were in the block 7539001 – 7560000 (Use of the numbers were discontinued in 1929). Reinstated after World War I in 1922, the militia was scaled back in 1929, following a reduction in funding, to a small volunteer force.
The militia was demilitarised in 1940, with all equipment being shipped to England just before the invasion of Guernsey by German forces.
One former member of the militia, Lt. Hubert Nicholle who had travelled to England in 1939 to join the Hampshire Regiment agreed to travel back to Guernsey by the British submarine H43 where on 7 July 1940 he undertook a successful reconnaissance of German defences in the Island during the lead up to Operation Ambassador, before being picked up on 10 July. Undertaking a second landing with fellow Guernseyman Lt. James Symes on 3 September 1940, in civilian clothing,  the pickup arrangements failed and the two were forced to surrender, after having obtained help from Ambrose Sherwill to get Guernsey Militia uniforms, being treated as POWs rather than shot as spies. Nicholle was awarded the MC.
The militia was reconstituted after the war, however in 1951 the States of Guernsey finally decided not to revive the militia.
Royal Guernsey Militia