The invention relates to a coating system, in particular a coating system containing an organometallic layer which allows the selective removal of post coating layers from substrates without detrimental impact to their “in-service” performance. The organometallic layer comprises (a) an organic polymer containing multi-chelating functionalities; and (b) a metallic agent which forms an organo metallic complex with the organic polymer containing multi-chelating functionalities and is located between an optionally coated substrate and at least one post coating layer of a coating system.