He has, until next year, the most remarkable admissions arrangements, which leave the school free to teach exactly whom it wishes to teach. These arrangements have enabled the school to choose parents who will be able and willing to pay pound;30 a month for their first boy's education and pound;15 a month for the second.
There are no constraints on parents, except that one must be a practising Catholic. Mr McIntosh can as easily take a pupil who lives miles away in Downing Street as one who lives next door to the school. He doesn't have to admit the cleverest pupils, but he can if he wants to.
Here's what he does, according to the London Oratory's brochure. He gets a report from the boy's present school about "ability, effort, attendance, punctuality, extra-curricular activities". He checks that the boy accepts "firm discipline". He asks for a commitment that the boy will stay at the school for the sixth form - he's not having them go off to a sixth-form college.
He interviews prospective pupils, with both their parents. This interview is "an important and decisive part of the admissions procedure". Its main function is "to assess whether the aims, attitudes, values and expectations of the parents and the boy are in harmony with those of the school".
Then the choice is made. Maybe the school takes the cleverest boys, maybe the most docile. Who knows? But Mr McIntosh certainly wants to know that the parents are motivated, because that, as every teacher knows, makes the school's job easier. Not for him the long, hard slog of teaching children whose parents do not value education.
He insists that he does not take the parents' social class into account. But no one ever expected him to turn away the boy whose mother was a top lawyer, and whose father looked set to become the next Prime Minister.
So now he probably has the sort of parents who will feel motivated to pay, and the chances are that quite a large proportion can afford to pay.
They will probably be glad to. The London Oratory will, after all, still be considerably cheaper than a fee-charging school, which is likely to cost at least pound;700 a month.
For next year, he has had to change these criteria. They now have to centre on religion, but he has been very clever in the way he has handled that. He will no longer be able to select pupils on their ability.
The interview will now "assess catholicity, practice and commitment" as well as the wonderfully open-ended "whether the aims, attitudes, values and expectations of the parents and the boy are in harmony with those of the school".
He will still be able to take account of the "commitment to the ethos of the London Oratory School" of both parents and prospective pupil, but he has put this under the heading of "religious criteria".
He's not by any means the first state school head to ask parents to pay. Some time in the past 20 years, we began tacitly to accept that schools need more than the state provides just in order to provide a basic education.
But in most schools, the sums requested are much smaller than those Mr McIntosh expects. Other schools have not had the luxury of selecting their parents, nor the luxury, under the previous government, of getting preferential funding, which would have helped make the school attractive to the sort of parents who would now be able and willing to cough up money. They have to set their sights lower.
Schools now rely on parents to give money, and raise money, to buy books and other essentials. They have to chivvy their parents out to the local branch of Tesco to collect vouchers so that they can have computer equipment.
A school which selects its pupils by ability - a grammar school - is also, along the way, selecting those parents who are more likely to be able and willing to do such things. Mr McIntosh has simply refined this down to a precise science.
Two weeks ago, the London Oratory's most distinguished parent announced the end of the class war. Tony Blair needs to do two things before this is more than empty rhetoric.
First, stop selection. Second, give all schools enough money for essentials, and only allow fundraising for luxuries.
Francis Beckett is the education
correspondent of the 'New Statesman'