Ségolène Royal and Nicolas Sarkozy traded insults on Wednesday night in a moment of high political drama during the televised debate between presidential finalists that captivated France just four days before the final round of elections.

Ms Royal accused her ­centre-right opponent of “political immorality” and Mr Sarkozy complained the Socialist had “lost her nerve” as the debate – France’s first in 12 years – lived up to its promise of fireworks between the contenders to replace Jacques Chirac in the Elysée palace.