With performances from Peter Capaldi, imagine... marks the 500th anniversary of Machi*elli's notorious book The Prince. Famous for lines like 'It is better to be feared than loved', The Prince has been a manual for tyrants from Napoleon to Stalin. But how relevant is The Prince today, and who are the 21st century Machi*ellians? Alan Yentob talks to contributors including Colonel Tim Collins, who kept a copy of The Prince with him in Iraq; plus Hilary Devey, Alastair Campbell and Game of Thrones writer George RR Martin.