Ministers have announced they are to consider letting state school students take International GCSEs courses - a qualification currently offered in a third of private schools.
Mr Richardson says IGCSEs should count towards league tables
In an article for the BBC News website, Nigel Richardson, head teacher at the independent Perse School in Cambridge, says the decision makes sense but issues a word of warning over league table ratings.
Lord Adonis's decision to consider letting state schools offer International GCSE courses makes sound common sense - but it also shows the absurdity of excluding IGCSE results from government performance tables.
As an alternative to conventional GCSE, it is very welcome.
If it at last bites this bullet, it will be offering them a freedom of choice which independent schools have enjoyed for some time.
My school was one which chose to reject the new-style maths courses in favour of the IGCSE equivalent several years ago.
IGCSE maths is more demanding, and free from coursework - an assessment tool which even the education department has now recognised is well past its sell-by date.
It is also a better preparation for A-levels and university.
Some of us also opted to go a stage further, by choosing IGCSE courses instead of the Twenty-first century science GCSE (C21) .
IGCSE centres on hard, scientific information, whereas C21 science GCSE has an emphasis on ethical and citizenship issues, and draws heavily on stories in the news.
It may well make the subject more accessible to pupils across the ability range.
But opinions about scientific issues need to be based on in-depth knowledge, and the GCSE courses do not seem suitable for a school such as mine with a strong scientific character and with 40% of leavers choosing science-related subjects at university.
Historically, the fact that all 16 year-olds take single sciences has been one of our strongest selling points with prospective parents - and pupils.
Nor are they fit for purpose for a school in what is arguably the UK's most scientific city, and the home of Silicon Fen.
So far, so good. But our initiative comes at a price.
Schools, including some of the country's most academically successful, are taking IGCSEs and are set to be given a nil score in performance tables due out in January.
This is because the Department for Education and Skills has ordered schools to take out IGCSE scores from its submissions of results. Why?
For the first time this year, these tables will show the proportion of teenagers who have achieved five GCSE passes at grades A-C, including English and maths - part of the new, so-called gold standard indicator.
But IGCSE is not officially recognised by the Qualifications and Curriculum Authority. Hence our zero rating.
This nil score will be a badge which we wear with wry pride, but also with bemusement and concern.
Pride, because we believe that we are giving our pupils the best preparation available for maths and science at A-level and beyond.
Because we are demonstrating that the very nature of our independence allows us to innovate and be different - a situation which any monopoly threatens - even in education.
Our concern is not merely selfish.
Yes, our pupils are very privileged in some ways, and after years of benefiting from the free publicity that selective schools derive from league tables, coming bottom will be a new experience.
Yes, to complain will seem either like crowing, advertising ourselves or whingeing.
But for all pupils - whatever their school - discounting high achievement in demanding courses is unjust.
The truth is though they will not really be affected, because top universities, including Imperial, have told us they are more than happy to accept applicants with IGCSE.
It does the credibility of the discounter no good either - such a narrowness of view about what constitutes gold standard performance flies in the face of all the simultaneous government initiatives to counter the critical shortage of applicants for undergraduate and postgraduate teaching diplomas in 'hard' science - and the threatened closures of hard science departments in some high-flying universities.
Competing with other schools
We also have a genuine concern for others tempted, but fearful, of following us down this IGCSE path.
Our parent clientele prizes rigorous courses more than performance ratings, but schools elsewhere may be more vulnerable to local competition.
Since I was a pre-teenager, science provision in schools has been transformed for the better.
In the 1960s, curriculum options choices were savage.
I became a near-total arts-sider at 14.
Whenever I do school assembly on a science/ethics topic, I live in uncomfortable awe of my young audience, regretting that newspapers which I read as an adult are no substitute for good maths and science learned at school.
Solicitors working on intellectual property, businessmen trying to steal a march in a scientific world market, and historians-turned-accountants must often feel the same.
Maths and science dominate our lives as never before. Do the "Powers that be" really want to go on sending out a message that they are so lowly valued?
So two cheers at least for Lord Adonis. If he opens up IGCSE opportunities to candidates from all types of school, he will be doing them a great service.
But can we expect a third cheer, for a simultaneous rethink of how the performance tables reflect this new thinking?
If not, it will merely hasten the public's increasing scepticism of all such tables? Ah, now there is a cause for hope.