BBC's Today programme holds an annual poll to find out which law its listeners would like to repeal.
One of the options this time was the 1701 Act of Settlement, which requires Britain's monarch to be a Protestant and forbids the monarch or heir to the throne marrying anyone not C of E.
The man proposing the repeal of this particular piece of discriminatory legislation was award-winning author and historian William Dalrymple, an expert on Asian religions as well as being the presenter of a prize-winning radio series on British spirituality and mysticism.
You probably won't have heard this interview because it was broadcast about 7.25 one morning last week but Jeffrey Donaldson came on to say why the Act of Settlement should not be repealed. It was priceless stuff.
Poor Jeffrey claimed the law had to be retained because, among other things, a Catholic monarch would have to give allegiance to the pope who is also a head of state and, wait for it, that would mean a diminution in British sovereignty.
So that obviously means the real ruler of Spain is a German pope. The same goes for Belgium.
You thought Zapatero was elected to govern Spain and Guy Verhofstadt Belgium? No, according to the DUP mind, the real ruler of these modern democratic states is not the elected head of government but the hereditary monarch who's in thrall to the pope.
Can Jeffrey really believe that? Sadly it seems he can.
Dalrymple, who was supporting his proposal in the same interview, claimed that the BBC had to dredge up a unionist who else? to support the retention of this discrimination because they couldn't find anyone in Britain to defend it.
Dalrymple's exasperation was obvious to all listening because our wee Jeffrey just didn't geddit. It just never occurred to him that Dalrymple, a noted expert on the religions of the Indian sub-continent, was talking in the context of modern Britain, a context that remains eternally beyond the grasp of unionists.
For people like Dalrymple it's important to repeal the Act of Settlement not only to demonstrate equality before the law to Catholics, a concept unionists have never come to terms with, but even more important in Britain nowadays, to demonstrate equality to Muslims, Hindus and Jews.
Our Jeffrey never thought for a second that by supporting the Act of Settlement he was advocating discriminating against Jews and Muslims and Hindus, now a sizeable proportion of British society. Jeffrey could only see the Act of Settlement in its 1701 context when the only bogeyman was the pope.
You have to laugh.
The interview provided a crystal-clear example of the gap between unionists' idea of Britishness and current thinking in Britain.
Stand by this year for an outpouring of books and articles and programmes on the concept of Britishness. May marks the 300th anniversary of the Act of Union between Scotland and England which officially invented Britain as a state.
Westminster is intent on formal commemoration of the event, unlike with the 1801 Act of Union anniversary six years ago.
Will the SNP use opposition to the anniversary of 1707 as a springboard for the Scottish parliament elections the following week? Do most Scots see themselves first and foremost now as British, or Scottish? The indications are most Scots have had enough of being run from London.
One certainty is that in all the analysis and soul-searching this year about the meaning of Britishness there'll be no place for the lost tribe in the sick counties.
As far as the majority of people on the other island is concerned the sort of embarrassing nonsense professed by Jeffrey Donaldson is an unrecognisable form of Britishness, a version fossilised in the 17th century which everywhere else was dissolved in the melting pot of 20th century Britain.
Perhaps the most dispiriting observation you can make about Jeffrey Donaldson's bizarre defence of the Act of Settlement is that he is representative of the next generation of unionist leaders.
The current leadership is a political Jurassic Park but if the mindset exhibited on the Today programme is anything to go by, then the prospect the coming men offer is back to the future.