Spotted in a the journal INS a review of Edward Lucas's book, Deception: The Untold Story of East-West Espionage Today, published 2013, that the book's capstone was:
remarkable interviews with the imprisoned Simm
Edward Lucas is an Economist writer, based in London, with a stint in Moscow. The interviews are an 'exclusive' from a comment by a reviewer on:https://www.amazon.com/Deception-Unt...spionage+Today

Or UK:https://www.amazon.co.uk/Deception-U...spionage+Today

INS in full is Intelligence and National Security which is published six times a year, with a global group of academic and other contributors. The review is behind a paywall.