We present a catalogue of 618 high-amplitude infrared variable stars (1<{Delta}K<5mag) detected by the two widely separated epochs of 2.2{mu}m data in the UKIDSS Galactic plane survey, from searches covering ~1470deg^2^. Most were discovered by a search of all fields at 30<l<230{deg}. Sources include new dusty Mira variables, three new cataclysmic variable candidates, a blazar and a peculiar source that may be an interacting binary system. However, ~60 per cent are young stellar objects (YSOs), based on spatial association with star-forming regions at distances ranging from 300pc to over 10kpc. This confirms our initial result in Contreras Pena et al. (2014MNRAS.439.1829C, Paper I) that YSOs dominate the high-amplitude infrared variable sky in the Galactic disc. It is also supported by recently published VISTA Variables in the Via Lactea (VVV) results at 295<l<350{deg}. The spectral energy distributions of the YSOs indicate class I or flat-spectrum systems in most cases, as in the VVV sample. A large number of variable YSOs are associated with the Cygnus X complex and other groups are associated with the North America/Pelican nebula, the Gemini OB1 molecular cloud, the Rosette complex, the Cone nebula, the W51 star-forming region and the S86 and S236 H II regions. Most of the YSO variability is likely due to variable/episodic accretion on time-scales of years, albeit usually less extreme than classical FUors and EXors. Luminosities at the 2010 Wide-field Infrared Survey Explorer epoch range from ~0.1 to 10^3^L_{sun}_ but only rarely exceed 10^2.5^L_{sun}_.