From Longman Dictionary of Contemporary Englishbe (at the) top of the list/agendabe (at the) top of the list/agendaIMPORTANTsomething that is at the top of a list will be dealt with or discussed first Europe is once again at the top of the political agenda. → top
Examples from the Corpus
be (at the) top of the list/agenda• Improving education is at the top of the mayor's agenda. 