"North Sea Reduced Coordination Area"
Within Cotrolled Airpsace at all levels, inclusive of FL 195 to FL 245, except during periods of notified activation of TRA 5, 6, 7A, 7B.Note 1: Within active TRA lower limit is raised to FL 245.
UK AIP ENR 2.2 section 6 (
https://www.aurora.nats.co.uk/htmlAIP/Publications/2019-08-15-AIRAC/html/index-en-GB.html)