Just read this in the Japanese
Asahi Shimbun that holders of passports from Japan, the US, Canada, Australia, and New Zealand will be able to use E-Gates at UK airports. This is not a "trusted traveler" program and there will be no registration required. There is no effective date in the article.
The Mirror today also published a similarly vague article, without mentioning when this would start.
For returning Britons, this may slightly delay their re-entry home. For visitors like myself, hopefully it will help shave what can sometimes be hours-long waits to clear immigration at Heathrow.