Angela Merkel made her strongest intervention yet in the German election campaign, using her last speech in the Bundestag to implore voters to choose Armin Laschet and warn of the dangers of a leftwing government for Germany.

Merkel said Germans faced a choice between a coalition made up of the Social Democrats, Greens and the hard-left Linke party and a government led by Armin Laschet, the candidate of her centre-right CDU/CSU, “a moderate government which will lead our country into the future”.

The unusually partisan intervention by Merkel, who is standing down this year after 16 years as chancellor, reflects the increasing nervousness in the centre-right camp at the commanding poll lead established by the Social Democrats in recent weeks. A new poll by Forsa for RTL/ntv-Trendbarometer put the SPD on 25 per cent, the CDU/CSU on 19 per cent and the Greens on 17 per cent ahead of the September 26 vote.