Peter Tyrie Duff’s grandfather, Peter Duff, married Mary Tyrie in Stanley, Perthshire in 1850. They lived in Clunie, Perthshire, and had eleven children, one of whom was Peter's father, Alexander Duff. Peter Tyrie Duff was born in Canisbay, Caithness, on 12th May 1899, the son of Alexander Duff and Annie (Mackenzie) Duff. His father was the schoolmaster there before moving to Milnathort.

In 1901, the Duff family were living at Bridgefauld, South Street, Milnathort. Father, Alexander (Teacher, Elementary School), b.1869; Mother, Annie M., b.1872; Daughter, Elizabeth M., b.1896; Son, Peter T., b.1899; and Catherine Wood (General Servant Domestic), b.1886. Peter Tyrie Duff was educated at Orwell Parish School and Perth Academy.

He enlisted, aged 18, with the 3rd Battalion, King’s Own Scottish Borderers (Reg. No. 26757) on 19th February 1917 whilst employed as an Apprentice Law Clerk with J & G Wilson, Solicitors in Kinross.

He joined No 10 Officer Cadet Battalion, at Gailes, on 7th September 1917 and was commissioned on 20th February 1918.

Extract from the 1/5th Battalion, South Lancashire Regiment, War Diary 1915-1919

“On the night of 16th/17th September, 1918 the Battalion took over the outpost line of the Brigade on a frontage of 1 mile.

At 6.30 am on the 20th September the Battalion attacked the enemy’s outpost system on a frontage of 1,250 yards, and advanced 400 yards, capturing 39 unwounded and 4 wounded prisoners. A fair number of enemy were killed in the assault (20 is a conservative estimate) and many more casualties were caused him by active sniping and Lewis Gun fire after the objectives were gained.”

Peter Duff would have been the platoon commander of one of the six platoons mentioned below:

“OPERATIONS. Left Brigade"

“At 6.30 am today (20th) in conjunction with attack by 2 Company’s of Division on our left, 6 platoons left Brigade, attacked and captured line of pill boxes and dugouts running from S.29.b.12.60. to junction NORA & SERPENT TRENCHES. All objectives gained - 41 prisoners, Patrols pushing forward to exploit success. Our casualties very light. Objectives were - Two pumping stations, and two sets of pill boxes at junction SERPENT & SPOOK TRENCHES and NORA & SERPENT TRENCHES. We are in touch with Brigade on left at Junction NORA & SERPENT TRENCHES.” This operation continued throughout the day of the 20th September with continued enemy resistance and artillery retaliation." 

There are references to a number of men being killed or posted missing. Peter Duff would have been one of these casualties. He was 19 years old. Peter Duff was buried in Houchin British Cemetery, he is also commemorated on the Orwell Parish War Memorial, Milnathort