That's a really important, interesting but difficult question to answer! It'll take a whole change in thinking, which will have to happen at multiple political, cultural and educational levels. At the moment, a shift to explicit colonial and nationalistic critique has only really happened in two areas: at university level, where obviously the numbers (as a proportion of the population) are very low; and, as we've seen in the last couple of weeks, on the streets. That we've seen conservative (and Conservative) pushback to both is very telling. Other levels that need to change: school curriculum (in recent years we've gone backwards in that sense, with Michael Gove's 'reforms' pushing us toward a more patriotic approach in history); the press/commentariat (which, I'd argue, is rather right-wing dominated and apologetic for Empire); and a critique/change in general popular culture, from film and television (less programming about British exceptionalism like the Dunkirk myth) to memorialisation (such as statues and annual commemorative rituals, like for WWI, that don't engage with the actual historical context of conflicts). It's a massive task!