If we go way back into CAP53 pre 1998 it states:
A revalidation Flight Test which is a first multi-engine test must include (f) at paragraph 4.
4
(f) Flight with Asymmetric Power
(1) Control of the aeroplane and maintenance of a given heading and asymmetric climb speed, following the failure of one engine in the climbing configuration at normal climb power.
(2) Identification of the failed engine and the completion of all essential drills and checks.
(3) Climbing and level turns in asymmetric flight as directed by the Examiner.
NOTE: Throughout item (f) of the test, the Examiner will be responsible for navigation and ATC liaison. On resumption of normal flight the candidate will be told the position of the aeroplane. Feathering will be simulated by the Examiner on completion of the correct touch drills by the candidate.
There have not been any changes to the IMC rating since the demise of CAP53. LASORS was a straight copy from CAP53.