Please find here the link to the BBC Radio interview.
Analysis: How Voters Decide, Part 1 will be broadcast on BBC Radio 4 on Monday 20th Feb at 20:30 (repeated Sunday 26th at 21:30). http://www.bbc.co.uk/programmes/b08ff18d
Analysis: How Voters Decide, Part 2 will be broadcast on Monday 27th Feb at 20:30 (repeated Sunday 5th March at 21:30).