WWW and
BIK
You both need to re read the books
In UK Class A, B, and C (though we don't have any of the latter), there is NO LIMIT at any time, unless specified, for example on departure SIDs out of LHR or inbound STARs.
In Class D, ATC may authorise relaxation of the speed limit if they wish and can meet some conditions.
For all other classes, which includes Class E controlled airspace, there is a mandatory 250Kts below 10K restriction.
http://www.ais.org.uk/uk_aip/pdf/aic/4Y291.PDF