1. A method for use in a cache hierarchy including at least two cache levels organized as a lower cache level and a higher cache level, each cache level configured to store one or more cache lines, the method comprising the steps of: providing a tag store at each cache level, the tag store containing tag values associated with the cache lines stored at the respective cache level, the tag values being settable between a valid state and a invalid state; comparing at least a portion of the tag store of the lower cache level with a given tag value; if the given tag value matches a tag value of the tag store, determining whether the matching tag value is in the valid state or the invalid state; and if the matching tag value is in the invalid state, bypassing the higher level cache.