Well, lets say the day would be midsummer day for argument, since its nice to have a day off in the summer, but still what does Gordo actually mean if:

he'd like to see all the relatively recently immigrated British people from Asia, Africa, the Caribbean etc support the notion of being British and proud of it before anything else
Specifically, Gordon, what would happen on this British day to make this true? Just to be a bit controversial here we could have a big lecture on the need to not be racists who think a woman's place is chained to a sink, and that in Britain religion has no role to play in public life and if you want to live under bloody sharia bugger off to Saudi Arabia, which would be a lot more constructive than a load of flag waving. But somehow I doubt Gordon had that in mind.

(NB yes I do know not all, or even most, immigrants think they have the right to beat their wives.)