Most of the VOR's in the UK are owned and operated by NATS. They are 1960's technology for which spare parts are no longer available and any repairs have to be constructed from scratch.
Advances in navigation have rendered many ground based facilities as unnecessary. NATS had planned to turn off the vast majority of UK VOR's by 2015 but that timescale appears to be slipping (as always happens with NATS target dates). But they will be withdrawn in the next several years.