There are two major problems. Recognising hidden talent is not easy.
Politicians' statements suggest it is just a matter of brandishing a few "American aptitude tests" (why are they assumed to be better than British ones?) to smoke them out from the slums. At the first sniff of these morsels of paper magic, hordes of troglodyte geniuses are supposed to emerge eagerly to claim first-class degrees three years later.
The second and related problem is that, whatever some believe to the contrary, generations of poverty and deprivation are potential killers of academic aspirations.
Many working-class families fight for survival, their health ravaged by poisonous traffic fumes, living in damp and inadequate housing, or working in lousy jobs - if they have one - that pay a pittance and blight people's dignity.
Identify a pupil who might benefit from higher education and there is immediate pressure on the poor beggar to grab a job if one comes up.
Previous attempts to find the Heineken intellectual test, that reaches the parts other tests cannot reach, have been disappointing. Even A-levels are modest predictors of degree class, though they are better than most alternatives.
Part of the reason is that most university students will get an upper or lower second-class degree, having entered with an A, B or C grade. In other words, we are using a relatively thin band of measures to predict an even thinner band of outcomes. Hence the relatively low correlations obtained.
One approach is a so-called "culture free" or "culture fair" test, which does not prejudice children from poor homes. But most items meant to identify potential have a cultural basis, even if this is the English language or a familiarity with concepts that the disenfranchised may have missed.
There is a better way. Schools should identify such students with potential on the basis of their long association with them, so universities could then look at them closely.
Ministers are now said to be happy to set up an "access regulator", the supreme watchdog who will ensure that universities recruit more working-class children. Do not believe it. I have even found a copy of the access regulator's culture fair test of clever working classness. Ten out of 10 and you are straight into Oxbridge.
Smart public school toffs will probably don cloth cap and muffler and pay a fortune in private tuition fees to perfect the answers. They should remember not to blow their cover by saying: "Ey up, old bean," in their interview.
Access Regulator's Culture Fair Test of Clever Working Classness Time allowed: two hours (time-and-a-half on Saturdays, double time on Bank Holidays and night shifts).
1 How many 10p coins will fit into a large three pound jam jar? How many such jars would it take to pay your top-up university fees?
2 Is keeping coins in a jam jar better than joining a Christmas club or putting a tenner on Kemptown Boy in the 2.30 at Doncaster? Give reasons for your answer.
3 When wiping your nose on your sleeve, which part of the sleeve is likely to be least conspicuous?
4 How many peas can you balance on your knife at one go?
5 At a college dinner you are asked to say grace. Do you: a) intone a piece of Latin?
b) say "Bless us and these"?
c) recite several minutes of nonsense so that you and your mates can grab the best food while everyone else's eyes are shut?
6 How many bags of nutty slack will fit into the average-sized tin bath?
7 How much is a full set of polyester leopardskin seat covers for a Ford Capri if:
c) on offer by a bloke in a pub as "surplus to requirements"?
8 Either a) draw a diagram with instructions for converting an attic or a coal shed into a pigeon loft, or b) describe how many sheets of corrugated iron, used floorboards and six-inch nails you would need to construct your own from scratch.
9 Write an essay, Me and my six whippets.
10 Your Aunty Doris tells you she has just been to the hairdresser. Do you say: a) "Yes, it suits you."
b) "It looks very ginger, but it'll match the cat."
c) "Were they shut?"