  In this paper we present visible range light curves of the irregular Uranian
satellites Sycorax, Caliban, Prospero, Ferdinand and Setebos taken with Kepler
Space Telescope in the course of the K2 mission. Thermal emission measurements
obtained with the Herschel/PACS and Spitzer/MIPS instruments of Sycorax and
Caliban were also analysed and used to determine size, albedo and surface
characteristics of these bodies. We compare these properties with the
rotational and surface characteristics of irregular satellites in other giant
planet systems and also with those of main belt and Trojan asteroids and
trans-Neptunian objects. Our results indicate that the Uranian irregular
satellite system likely went through a more intense collisional evolution than
the irregular satellites of Jupiter and Saturn. Surface characteristics of
Uranian irregular satellites seems to resemble the Centaurs and trans-Neptunian
objects more than irregular satellites around other giant planets, suggesting
the existence of a compositional discontinuity in the young Solar system inside
the orbit of Uranus.
