President Nicolas Sarkozy is suffering his first serious political troubles since coming to power, amid mounting criticism from inside his party, dissatisfaction over his economic policy and plunging opinion poll ­ratings.

Mr Sarkozy’s net popularity has fallen by 13 points since the start of the year, according to a poll by LH2 for Libération newspaper, taking him to lows reached by his predecessor, Jacques Chirac, in 1996.