A landmark judicial review of police practices at last year's Royal Wedding will begin later.
Measures examined will include the use of 'pre-crime' arrests - which were employed before the wedding.
The findings will likely impact future policing at upcoming events such as the Jubilee and Olympics.
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The 'Theatres at Risk' register lists venues across the country that are most likely to be lost and calls for local authorities to intervene
The assault took place after a woman got on the train from Oxford Circus station with three children aged between two and five.
The sex offender was reportedly transferred from HMP Wakefield in West Yorkshire to HMP Belmarsh, south-east London.