Time to update your calendars, everyone! It's the start of the White Season!!

Or, to be wholly specific, it's the start of the BBC's “How the White Working Classes are Coping with Mass Immigration Season”. As an almost entirely unprecedented tackling of the subject, it's already been heralded as the BBC “opening the floodgates” to racist polemic at the nation's pub tables and water-coolers. In terms of potential political fall-out, it makes a “Lesbian Season” on Channel 4 look like a “Kittens Wearing Mittens Season on Living”.

Starting on Friday with Last Orders, White Season - comprising five documentaries and a drama, White Girl - sketches out its landscape quite quickly: Britain is a country entering the second stage of a gigantic social experiment - multiculturalism through mass immigration - for which, amazingly, no particular plans, projections or provisions were ever made. While immigration might be something the liberal left-wing are in favour of - and find very useful, vis-a-vis Ukrainian carpenters on £2 an hour - it is, in the main, the working classes who are actually living this multicultural life, and sharing their shops, schools, hospitals, pubs and streets with dozens of different nationalities, cultures and beliefs.

A large part of the hitherto selfimposed broadcasting ban on discussing immigration can be laid at the doorstep, doubtless spotlessly white, of Enoch Powell and his “Rivers of Blood” speech. As the logical starting point for any debate, it's rather baffling that Rivers of Blood doesn't open the season. As the documentary makes clear, Powell's speech was such a Hiroshima of oratory - an outpouring of such extremity - that it deterred any Establishment discussion of immigration for 40 years.

Most of us will never have seen the whole speech - because the BBC cameraman filmed only parts of it. Watching what there is proves instructive: Powell, with his tiny pupils and raptor's head, looks like a peregrine falcon, and frames gut-fears in the language of a prophet-statesman. The seduction was so instant that had public polls decided such a thing, Powell would have become Prime Minister of Great Britain that week - and by a landslide.

Rivers of Blood is a classic, authoritative BBC documentary on a difficult, fascinating subject, with loads of satisfying archive footage of people with 1960s hair coming out of factories, and sitting in pubs. It's 45 minutes of total Licence Fee Justification broadcasting.

Speaking of those pubs, Last Orders documents the dying days of Wibsey Working Men's Club. Where once the club was the heart of the white community, it's now a relic - anachronistic in the young, increasingly Muslim city of Bradford.

Last Orders is, at 90 minutes, dreary, achingly over-long, and misguidedly sentimental. By the end, you are apt to feel that if these people can't even - pretty much literally - arrange a piss-up in a pub, it's no wonder that their city is being taken over by people with a bit more zazz.

And visually, the documentary concurs: along with Storyville, Last Orders - whether intentionally or not - shoots the old, white working classes as grotesques: crater-pored, cross-eyed, with tiny, pinprick eyes, mouths so wrinkled from smoking they look like combs, and noses crystalline with gout. They all look like Breughel peasants - unimaginably distant from the modern world of smoothies, iPhones and Lewis Hamilton. They look, unkindly framed, like they need to die out - although whether they should be replaced by, say, a tight-knit community of Muslims living under Sharia is another matter.

Storyville, as usual, winkles out a better plot with All White in Barking. Nosing around Barking, Essex, it finds a couple of stories that give a far more nuanced vision of a fast-changing, multicultural area - including the BNP campaigner who, in one scene, tries to hand a racist leaflet to his daughter's half-black boyfriend.

Ironically, he actually seems to have the colour-blindness (“He's half African? Are you sure? I'll have to check that out”) that the idealistic liberals who originally conceived multiculturalism dreamt of.

It's just one facet of the current British working-class experience that makes this season such a great - and, rarely for TV, significant - intellectual chewing-point.

BBC Two's White Season begins with Last Orders on Fri, 9pm, and continues the following week with Rivers of Blood, All White in Barking and three other films: White Girl, The Poles Are Coming and The Primary

Editor's choice

• The 100 Best Films of the Decade
• 70 facts you didn't know about Marvel
• The 50 Biggest Movies Of 2010