Sir Michael Wilshaw on the 'North South divide' in English schools

"Politicians in Manchester and Liverpool will have to accept that the Northern Powerhouse will splutter and die if their youngsters lack the skills to sustain it."

That was the stark warning from the chief schools inspector in England. Sir Michael Wilshaw says there is a performance gap between schools in the North and Midlands and those in the South - which seems to be getting worse.

Sir Michael spoke to Martha Kearney on the World at One.