SERA is a European regulation. It has the force of law in the UK and other EU countries. In case of a contradiction between UK statute and SERA, SERA prevails.
Nevertheless, there are still options open to countries within SERA. See CAA Website and the several information notices which were recently issued.
SERA in fact did not harmonise much.
Most of the EU states had already almost ICAO compliant rules of the Air.
Most of the differences between previous local rules are still with SERA left to the appreciation of each country.
For instance: ICAO and SERA do not require a flight plan to be filed for IFR AOCAS.
France before SERA required it.
SERA allows a country to require a flight plan to be filed on specific routes within uncontrolled airspace.
France decided that its entire uncontrolled airspace is such a specific route. So that nothing changes in France.
Each country does its best to keep things as they were before.
This is typically what happens when the same countries meet and decide that it would be great to harmonise something and make a new regulation. It does not harmonise anything and keep lawyers busy.
Last edited by 172510; 26th Mar 2015 at 18:35.
Reason: spelling