It has been a rough year for the BBC, but its programmes have never been better. It ends the year with two dramas of towering intent and execution.

Sunday night saw the first part of Small Island, adapted from the Andrea Levy novel. And for Christmas we have the second series of Cranford. We have Judi Dench back in her bonnet and can rest easy. Small Island — largely filmed on location in Northern Ireland — is also first-class drama.

When Greg Dyke called the BBC “hideously white” he spread a panic about the lack of ethnic diversity. But one should be realistic about representation.

Jane Austen was just not very diversity-minded. It would have been a pity if the BBC had ditched Austen as a result.

Dyke was also unobservant about the different geographical demographics of Britain. I remember a lunch with a television big cheese, the Daily Telegraph columnist and BBC licence martyr Charles Moore. The television chief talked of the scandalous lack of ethnicity on screen, relative to the British population. I nodded furiously, citing my experience of London. Charles pointed out television wasn’t underrepresenting the ethnic population of Sussex.

Race on television has not been an issue this year, making the superb production of Small Island all the more potent. From nowhere, comes a drama of such humanity and comedy it is life enriching. Coincidentally, it’s being shown days after the all-black cast of Cat on a Hot Tin Roof won praise from critics.

You will not see finer acting on television this year than from Naomie Harris, playing Hortense in Small Island, the haughty, vulnerable young Jamaican wife, or from David Oyelowo, her striving husband, Gilbert, or from the white actress Ruth Wilson, as Queenie, the landlady at the emotional heart of the drama. In spite of its crude racism — “no niggers, no dogs, no Irish” — in its way it was an age of migration innocence. The newcomers carried British passports and pledged allegiance to the Queen.

Hortense and Gilbert talk always of the Mother Country. The prejudice they encounter is fear of the unfamiliar, rather than anything more organised.

What makes it such compelling television is the personal relationships. Hortense is cold at the start until she finds her proudly held teaching qualification counts for nothing in Britain. Her exasperated husband is grateful for the unexpected tenderness she eventually shows. Queenie tests the limits of society by her love-affair with a Jamaican. It is a tough and tragic tale but fellow-feeling and human dignity prevail.

Each wave of immigration brings social tensions and anxiety. Yet the many who arrive here, work hard, prosper, settle. The real point of diversity, on television and in life, is not that is correct but that it is vibrant.