He commanded the 33rd at Arras in 1917, with mixed results, and through the German spring offensive in 1918, where the division helped stabilise the defensive line after the Portuguese Expeditionary Corps (CEP) was routed.

After the war, he retired to rural Dorset, where he served as a local justice of the peace, as High Sheriff for the county, and as a deputy lieutenant, before his death in 1943.

[1] At least one of Reginald's brothers, John, also passed into the armed forces, joining the Central India Horse of the British Indian Army.

[14] He held this posting until July 1913 when he was transferred back to England to command a reserve unit, the Devon and Cornwall Brigade of the Wessex Division, a formation of the part time Territorial Force (TF).

[1][15] Following the outbreak of the First World War in August 1914, the British Expeditionary Force (BEF) of seven Regular Army divisions was mobilised for service in France.

[23] The 8th Division, under the command of Major-General Francis Davies, was sent to France in November; immediately after arrival, two battalions were deployed to hold a section of the front line for a week during the closing stages of the First Battle of Ypres.

[25] Pinney's 23rd Brigade met heavy resistance when it began its attack, due to a failure by the divisional artillery to bombard a large section of the defenders' trenches; the 2nd Middlesex, making a frontal assault, were wiped out almost completely.

The division was mainly drawn from industrial areas of Northern England, with a high proportion of "bantams", men who were under the normal regulation height of 5 ft 3 in (160 cm) for army service.

[39] However, some of his habits were unpopular; most gallingly to his men, he stopped the regular issue of rum in the division shortly after taking command, replacing it with tea instead.

[47] This was followed by a series of attacks on the Hindenburg Line in late May, the first of which, on the night of 20 May, was masterminded by Pinney[40]—one observer noted that "his tail is right up over his back ... he was out for a gamble with his troops and he had it", though sadly added that despite its great success, he still refused to authorise an issue of rum.

[49] Following the fighting around Arras, the 33rd was moved to Nieuwpoort, Belgium, as part of the build-up for the planned Operation Hush, a breakthrough along the coastal front coupled with an amphibious landing behind German lines.

[50] After the operation was cancelled, the division remained at Niewpoort, where Pinney was hospitalised and temporarily relinquished command of the 33rd to Brigadier General Philip Wood.

During the Battle of the Lys, the Portuguese Expeditionary Corps (CEP) was effectively wiped out, leaving a two-mile wide gap in the British lines.

The 33rd was ordered into position, and Pinney personally commanded the divisional machine-gun battalion, which—with the assistance of various stragglers from retreating units—helped turn back a heavy German attack at the Battle of Hazebrouck on 12 and 13 April.

[42] At the Selle, Pinney organised a dawn attack with improvised bridges, allowing the 33rd to force a bridgehead and successfully clear the opposing bank in a short time.

[1][54] Following the end of his career in the army, Pinney took up residence at Racedown Manor, in the village of Broadwindsor, Dorset, where he lived the life of a retired country gentleman.

[58] His daughter Rachel was one of a group of women who, as "Ferguson's Gang", hit the headlines in the interwar period with masked appearances with bags of money to save properties for the National Trust.

[59] A scholarship fund, to provide access to higher education for the children of Dorset ex-servicemen, was established in Pinney's name in June 1943,[60] and remains in existence.