From DfT 14.1.16
EAPC electric bikes
Thank you for your correspondence dated 11 December and 5 January to the Department for Transport with regards to Electrically Assisted Pedal Cycles (EAPCs).
Please find attached a draft information document which should answer your questions.
We hope this helps in clarification of EAPCs in the UK.
Guidance on European Type Approval for certain Electrically Assisted Pedal Cycles (EAPC) 2016-01-14
Twist and Go type approval from Jan 2016