A crosslinkable composition including at least one crosslinkable component that is crosslinkable under the action of a base catalyst, a first carbonate salt according to a first formula as latent base crosslinking catalyst, and a second carbonate salt according to a second formula as potlife extender, wherein the second carbonate is present in an amount of at least 5 mole % and preferably at most 500 mole % relative to the molar amount of the first carbonate. Further disclosed are catalyst compositions composed of the first and second carbonate salts, to the use of the catalyst composition as base catalyst system in crosslinkable compositions and the crosslinkable compositions, in particular coating compositions comprising the catalyst composition.