Programme Making and Special Events (PMSE) use a lot of the (clear in the location) frequencies in the UHF TV broadcast spectrum; and always have.618MHz is firmly in the TV spectrum, it shouldn't be in use for anything else.
Also licence-exempt white space devices (WSD) can use the entire 470-694 MHz band - they 'find' clear frequencies to work on AIUI.
See http://static.ofcom.org.uk/static/spectrum/map.html for the approved use of frequencies in the UK.