In the first act of Richard Bean’s new play, a 17th-century Huguenot minister warns his fugitive Froggy flock to become English with all speed. What if a religious war breaks out, he asks, between the country they have abandoned and the one they have chosen for their new home: “Will you cheer for England or France?”

At least they were given a choice! When England lined up against Ireland in the Six Nations last weekend, my girlfriend flatly informed me that I was rooting for Ireland. Oh, and that the loser would undertake a naked midnight dash to the local NatWest (cf. ‘run on the bank’). It wasn’t the wager that got to me: NatWest isn’t that far, and I have pretty good legs. It was the fact I’d been relegated to bog-dweller status for an afternoon so that someone else could bolster her own Englishness. Which is, as everyone knows, a totally mythical concept anyway.

England People Very Nice is a two-and-a-half-hour potted – and occasionally musical and variously animated – history of immigration to our mongrel nation, from Romans (1: 14) to Huguenots to Somalis. Set in Bethnal Green, it makes use of documented people(s), places and things to chart the re-echoing story of how every wave of migrants sets about redefining both itself and England.

With a dark grin (not cynical, not pessimistic) Bean gives centuries-old characters lines about being the only Christian in the local school, or how the world will be more peaceful if the Jews are given their own country. Then there’s the need to carry identifying symbols; the willingness of newcomers to mix with the existing population; turbulent inter-marriage; hate-preachers; even tube-bombings. It’s not all roses, but we generally seem to muddle through. And the whole business is a play within a play, a motley collection of illegal immigrants rehearsing under the watchful eye of a put-upon social worker (the excellent Olivia Colman, pictured). The play – which they have “devised” together, while awaiting deportation – is about how liberal England is. More than once she threatens to cancel it.

It takes a certain boldness to confront people with the obvious, and a real talent to get away with it. OK, so gags about Stoke Newington’s champagne socialists and Irishmen and their pigs (I don’t have one, no) aren’t exactly new. But Bean’s ‘jokes’ are smartly delivered, and only as obvious as the truths which spawned them: as one English Protestant barks, “Not all Catholics are violent Papists; but all violent Papists are Catholic!” In 500 years, only the proper nouns have changed.

England People Very Nice is at the National Theatre until June 30. Tickets: £10-£30, tel 0207 452 3000 (