The nationalist Alternative for Germany party (AfD) made sweeping gains in regional elections on Sunday, inflicting heavy losses on Angela Merkel’s Christian Democrats (CDU).

Björn Höcke, a politician who has been compared to Hitler by German national television, led the AfD to second place in the eastern state of Thuringia with 23.8 per cent, according to initial projections.

The AfD was held off by the Left Party of the current regional prime minister, Bodo Ramelow, which came first with 29.5 per cent.

But Mr Höcke beat Mrs Merkel’s party into third place in a state it has dominated since German reunification.

Following a campaign that saw far-Right death threats against its regional leader, the CDU limped in with just 22.5 per cent – by far its worst ever result in a state where it has come first in every previous election since 1990.

With the centre-Left Social Democrats (SPD) also recording their worst ever result in the state with just 8.5 per cent, the mainstream German parties appear to have lost control of Thuringia. Instead the state is now starkly divided between the hard-Left and the hard-Right.

The result will be seen as personal vindication for Mr Ramelow, Germany’s first regional prime minister from the Left Party, a successor to the former East German communist party.

“I see myself strengthened. My party has a clear mandate to form the next government,” a triumphant Mr Ramelow said.

But the results were also a success for Mr Höcke, the most controversial figure within the AfD, who more than doubled his party’s share of the vote since the last election in 2014.

“Gains of more than 100 per cent have never been recorded before in the history of Thuringia,” a gleeful Mr Höcke told German television. “This is a sign that a large part of Thuringia says: ‘No more!’”

Mr Höcke is under observation by German intelligence as a possible threat to the democratic order.  In the course of the campaign he was described as a “Nazi” by the regional leader of Mrs Merkel’s party, and accused by the German interior minister of personally stoking an atmosphere of anti-Semitism that led to this month’s failed far-Right attack on a synagogue in Halle.

But he shrugged all that off to inflict heavy losses on his rivals. Although he did not match the 27.5 per cent the AfD won in Saxony earlier this year, he arguably scored a more telling blow by beating the CDU into third place.

He will now be expected to look to use that success to strengthen his position against his more moderate rivals within the AfD.

For Mrs Merkel’s party, the results were disastrous. “For the democratic centre this is a bitter result,” Mike Mohring, the regional CDU leader said. “For the first time a centrist government is not possible.”

Talks on forming a new regional government are expected to be protracted. Although Mr Ramelow claimed a mandate, he failed to secure a majority and there is no obvious coalition.

With the CDU refusing to join any coalition that includes the Left Party, and all other parties ruling out any alliance with the AfD, Mr Ramelow may be forced into forming a minority government.