If a mark is filed that you think is similar to your mark you may oppose it during the opposition period to seek to prevent it from becoming registered. In the UK this period lasts for 2 months after publication and for European Community Trade Marks (CTMs) it lasts for 3 months after publication.
It may not be necessary to file opposition proceedings against all similar marks, even where there is some degree of overlap in the marks and/or the goods and services they cover. For example, where the relevant businesses operate in entirely different sectors or markets, the owner of the earlier trade mark registration may agree that an amendment of the specification of the third party’s is sufficient to address its concerns.
However, on occasions where a compromise cannot be agreed it may be necessary to fully oppose registration altogether.