Conor Ryan refused to meet with exam boards when a Labour special adviser, which might explain his reaching for a simple, unworkable, solution to raising standards by creating a single English-wide exam board to stop schools and colleges “shopping around” (“OK, I admit it, the coalition’s got good ideas”, May 21).

The truth is that such shopping around is a myth and that aggregate market share between exam boards has remained remarkably constant for many years, usually only changing significantly when specifications change. A single examining board would militate against choice, diversity and innovation. Why would a single board be more efficient or more responsive than the current operators? And will politicians be happy to take responsibility for the failures of this single board?

And what about the Welsh, Scottish and Northern Ireland boards? Surely they would continue to exist, thus undermining the proposed “reform” from the first day.

A graver threat to standards is the constant chopping and changing of education policy and the use of assessment as an instrument to promote such changes. A move to a single exam board would make such political interference that much easier.

As Mr Ryan says, “the coalition’s got good ideas ...” not the least of which is its active endorsement of choice in qualifications, something that Mr Ryan’s dirigiste and centralising concept of a single exam board would directly undermine.

Bene’t Steinberg, Group director of public affairs, Cambridge Assessment.