The magnificent Caledonian Clock Tower, designed by James Bunstone Bunnings, was erected in 1855 as the centrepiece of the new Metropolitan Cattle Market, developed by the City of London Corporation to replace Smithfields as the livestock market for London. The tower and sections of the original market railings on Market Road and Shearling Way are all that survives of the market which originally occupied thirty acres of ground.

The tower contains one of the largest chiming turret clocks in London. It was supplied in 1856 by B.R. and J. Moore of Clerkenwell, whose printed catalogue lists a ‘Clock with four 10ft. 6in. dials, chiming, for the Cattle Market, Islington, London’. The bells were cast at Whitechapel Foundry and rang out at market opening and closing time as well as on the hour and quarter hours.

The tower is square in plan with seven stages, the first two wholly decorated with banded rustication, the third and fourth partly so. The sixth stage contains the clock faces which were originally glazed in opal glass with the hands driven from the clock mechanism housed in the louvered fifth stage beneath. The highest, seventh stage is arcaded, and partly enclosed by square stone pillars forming the clock bell chamber which houses a large hour bell and two quarter bells. It is surrounded by a projecting York stone balcony with a decorative cast iron balustrade to form a continuous square viewing platform supported by sixteen pairs of cast iron console brackets.