  We present the results of a proper motion wide-field near-infrared survey of
the entire Upper Sco (USco) association (~160 square degrees) released as part
of the UKIRT Infrared Deep Sky (UKIDSS) Galactic Clusters Survey (GCS) Data
Release 10 (DR10). We have identified a sample of ~400 astrometric and
photometric member candidates combining proper motions and photometry in five
near-infrared passbands and another 286 with HK photometry and 2MASS/GCS proper
motions. We also provide revised membership for all previously published USco
low-mass stars and substellar members based on our selection and identify new
candidates, including in regions affected by extinction. We find negligible
variability between the two $K$-band epochs, below the 0.06 mag rms level. We
estimate an upper limit of 2.2% for wide common proper motions with projected
physical separations less than ~15000 au. We derive a disk frequency for USco
low-mass stars and brown dwarfs between 26 and 37%, in agreement with estimates
in IC348 and sigma Ori. We derive the mass function of the association and find
it consistent with the (system) mass function of the solar neighbourhood and
other clusters surveyed by the GCS in the 0.2-0.03 Msun mass range. We confirm
the possible excess of brown dwarfs in USco.
