I have just watched Hardtalk on BBC World News with you and Rachel Wolf.
I find it rather depressing how the concept "free" schools now is conquering the UK.
Sweden and its "free" schools was mentioned several times - but not as a role mode..... (which the Swedish school system was let say 30-40 years ago). As you rightly pointed out our school system is slowly but steadily deteriorating and faling in international comparisons as Timms and Pisa. Today most researchers here (including the National Board of Education) explain this trend partly with an increasing segregation. Quite a number of them interpret this process as a result of "the freedom of choice for (some) parents" and the "free" school-system.
When the idea was introduced in the 1980ies/1990ies the arguments were very appealing - and romantic, e.g: now engaged teachers and/or parents could start schools which could develop new ideas and methods whích in turn the public owned schools could benefit of, it could be an arena for organizations of different kinds to contribute etc etc
Very few realized the risk and the challenge to the national school system. Two reasons for this were firstly the financial crisis that hit Sweden in the beginning of the 90ies. The cuts in the schools were tremendous. Secondly a very bad idea was realized: the state controlled schools were handed over to the local authorities. More and more parents had good reasons to look for alternatives. This in combination with the "freedom of choice"-ideology made it hard for those who wanted to defend the public schools (not in the English meaning) to make them self heard. They were even silenced - e.g. the biggest paper in the country, Dagens Nyheter, refused to publish their articles.
Not even the Socialdemocratic party were rooted in an ideological base strong enough to defend a public, national system.
This is the short version of the background to what then happened. After a while more and more schools were started by or transformed into private companies, e.g. Kunskapsskolan (by the way a really stupid or provocative name - kunskap meaning knowledge. What did they think the public schools were aiming at?). Now the arena is dominated by three or four big "educational companies" or groups in turn owned by venture capitalist making good profits which they have placed in different tax havens.
On top of that we have isolated right-wing christian schools, muslim schools etc. Of course, when inspected they always assure that they follow the school law and the national curriculum. And it is very hard for the Swedish Schools Inspectorate to show that they don't. Another problem are schools started by fortune-hunters that later have to be closed down because of low quality. The closures of these schools affect students who have been allured by the marketing of the schools and there are several cases in Sweden were yuong people have been affected in this way and lost a year or more of their education since they have had to start again in a municipality driven school.
Some politicians have now reacted but too late. E.g. how on earth can you in reality prevent these companies to make a profit? They can hide it in a lot of differnet ways: by internal invoices, rules when it comes to buy equipment etc.
I know that the "free" schools in the UK are defended with arguments like "we will never permit profits" etc. But some of the argument put forward by your counterpart in the program sounded like the ones presented in Sweden 10-20 years ago....
It is noteworthy that school choice is identfied as detrimental to pupil results in John Hatties giant meta-metastudie Visible learning. He argues that it is because of the segregational effect and loss of positive peer-influence. It is likewise noteworthy how the the by USA:s government ordered OECD report Standing on the Shoulders of Giants points out that the market inspired methods that have been tried (without success) in USA is almost contrary to how the most successful school systems in the world are built andwhat they emphasise.
So in short - I think it is worthwhile studying the Swedish case if you want to see what could become a reality in the UK in ten years time or so....