The cannon is one of two at this location, the other being a 4.7-inch gun M1906. Both pieces are in good condition with the bore plugged.
Wikipedia:
"The Ordnance BL 60-pounder was a British 5 inch (127 mm) heavy field gun designed in 1903–05 to provide a new capability that had been partially met by the interim QF 4.7 inch Gun. It was designed for both horse draft and mechanical traction and served throughout the First World War in the main theatres. It remained in service with British and Commonwealth forces in the inter-war period and in frontline service with British and South African batteries until 1942 being superseded by the BL 4.5 inch Medium Gun.
The effective use of modern heavy field guns by the Boers during the Second Boer War (1899–1902) was a revelation to armies in Europe including the British. They were impressed by their mobility and range. Britain used some heavy guns in that war under ad hoc arrangements. After the capture of Pretoria in 1900 Lord Roberts, the commander-in-chief in South Africa (and an artillery officer), had stated the requirements of a heavy field gun: a range of 10,000 yards, weight behind the team of no more than 4 tons and the largest possible shell, accordingly the Ordnance Committee in London ordered experimental guns and three were trialled.
However, in 1902 the Heavy Battery Committee was formed comprising officers experienced with heavy and siege artillery in South Africa and presided over by Colonel Perrott who had commanded the Siege Train there. In early 1903 their first report dismissed the 4.7 inch (120 mm, used in South Africa) and the 30 pounder (used in India) from further consideration because they lacked firepower. Of the three trial guns they accepted the Armstrong design but rejected all three carriage designs. New designs were sought that were easier for detachments to use. 1904 trials with a new design, including both horse and mechanised towing, resulted in further changes but in 1905 the design for the BL 60 pounder was accepted, although it was still a half ton over the target weight.
Unfortunately, in 1900 the Secretary of State for War had announced a plan to give "Volunteer Position Batteries 4.7 inch guns", he also extolled the merits of 4.7, (which the army knew to be misleading) and in 1902 and 1903 Parliament voted to equip 60 Volunteer batteries with a 4.7 inch, despite the 60 pounder being in development. The 4.7 inch had many weaknesses as a field equipment, but it had captured the public's imagination. However, in 1903 a heavy brigade RGA was formed by converting three siege companies and equipping them with 4.7 inch guns. The following year a second brigade was formed from three more RGA companies. These regular army brigades were part of the corps artillery, although their equipment was an expedient.
The 60 pounder gun was used on most fronts during the First World War and replaced the 4.7 inch guns. At the outbreak of war they equipped, with 4 guns, the heavy battery RGA in each infantry division. In 1916 all batteries on the Western Front started being increased to 6 guns. By this time heavy batteries had ceased to be part of each infantry division and batteries became part of what were eventually called Heavy Artillery Groups with several batteries of different types. After the First World War they equipped medium brigades, later regiments.
By the outbreak of war in 1914 41 guns had been produced, 13 being in Canada and India. Armstrong were the main supplier, with Vickers and the Ordnance Factory Woolwich also producing complete equipment. Major assemblies including barrels were also produced by many other companies. Total wartime production was 1,773 guns (i.e. barrels) and 1,397 carriages.
The 60-pounder was a heavy field gun or 'gun of position' designed to be towed by either a horse team or mechanical vehicle. It had a quick firing recoil, meaning that the carriage did not move when the gun fired. The barrel was a wire wound tube in a jacket with a screw breech. It fired a separate round (i.e. shell and bagged cartridge were loaded separately). The lower carriage comprised a box trail. It was designed for one-man laying with both traverse and elevation sights and controls on the left.
Mark I gun's recoil system was in two tubes above the barrel and used a hydraulic buffer with a hydro-spring recuperator to return the barrel to its firing position; Mark II gun had a hydro-pneumatic system below the barrel.
Initially the 60 pounder was fitted with tangent sights on a rocking bar with the range scale graduated to 10,400 yards and 22 degrees, the rear sight had a deflection scale. Before the First World War it was fitted with oscillating (reciprocating) sights, using the older No 5 sighting telescope (x12 magnification) on either Sight Oscillating BL 60 pr Mk I or II, which included a sight clinometer and range scale as well as a deflection drum for the telescope. This was replaced by the No 3 carrier for the No 7 dial sight."
Wikipedia