Tic, despite there being standard phraseology which ATC should adhere to inevitably a few non-standard phrases creep in.
In the London TMA we are frequently asked by aircraft (particularly inbound to Stansted) who are approaching the speed limit point if they can maintain high speed i.e. ignore the 250 kts speed limit. ATC may pre-empt this question by saying to the aircraft 'maintain high speed'. Also approaching the Lambourne hold when Heathrow are on 09 there is still a long way to go and if we know there is no delay we may say to the aircraft 'maintain high speed' again meaning disregard the speed limit point, which as it happens might be a better phrase to use on the R/T!