The Factory, an "alternative" venue in Hamburg's hip Altona district, was so full that police had to stop more people entering. Inside, crimson-faced and in front of a banner of the same hue, "Red Oskar" Lafontaine, the undisputed king of Germany's radical new "The Left" party was deep into a tirade against warmongers and capitalist neo-liberals.
The event was The Left's final rally in the party's campaign for Hamburg city state elections on Sunday in which Germany's mainstream political parties are set to lose votes to the new movement for the third time in just over a month. In similar elections in Hesse and Lower Saxony in January, The Left won seats in west Germany's main provinces for the first time in its brief history.
At the Hamburg meet, Mr Lafontaine, the renegade former Social Democrat leader once described by The Sun as Europe's "most dangerous man", accused Chancellor Angela Merkel's government of imposing neo-liberal "Thatcherite" policies on millions of impoverished Germans unable to survive on meagre unemployment and social security benefits.
Then it was Germany's "senseless" and "illegal" deployment of troops in Afghanistan that was singled out by Mr Lafontaine.
Quoting Germany's popular post-war Social Democrat leader Willy Brandt, he exclaimed: "Never again should war be conducted from German soil!" The 2,000-strong crowd roared and cheered in rapture.
Opinion polls suggest that the party will win up to9 per cent of the vote in Hamburg. That could be enough to deprive the classic political alliances made up of conservatives and liberals or Social Democrat and Greens of enough seats to win a clear parliamentary majority. In Hesse, The Left now holds the balance of power and as no other party will agree to form a coalition with them, the state is still without a proper government.
The prospect of something similar happening at a national level during Germany's general election next year is beginning to worry the country's established parties. With its populist remedies – which include a minimum wage, renationalisation of the energy sector , a super tax for the rich, and troops out of Afghanistan – The Left is winning the support of voters fed up with the middle-of-the road policies of Mrs Merkel's coalition of conservatives and Social Democrats.
The party started out as a reformed version of the former East German Communist Party after German unification in 1990 and only campaigned in the east. But last year it shifted west, recruited scores of disaffected ex-Social Democrats and more radical left wingers and renamed itself "The Left". Although the party shares power with the Social Democrats in Berlin, the Social Democrats dismiss a national alliance because The Left is too radical.
Mr Lafontaine, a former finance minister and Social Democrat party leader who was forced to quit both posts in 1999 after a furious row over the party's alleged drift towards neo-liberalism, has emerged as The Left's champion.
An opinion poll published yesterday by Germany's respected Allensbach institute showed that The Left is now easily the country's third political force after the conservatives and Social Democrats and has the support of 12 per cent of voters.
Mr Lafontaine insists that his party is a natural home for all Social Democrats who feel their party has deserted its socialist roots and for Greens who think their party has forgotten its pacifist traditions.
Yet The Left was shaken during its campaign after one of it members was exposed as a radical Communist with "loony left" tendencies. Christel Wegner, a newly-elected MP in Lower Saxony went on television and called for the return of East Germany's infamous Stasi secret police and suggested that the Berlin Wall was designed to stop West Germans going on shopping sprees in East Germany.
Mr Lafontaine attempted to make light of the affair in Hamburg. In a reference to Mrs Merkel who was brought up in East Germany and obliged to join the Communist youth movement, he said: "Even our Chancellor was once an enthusiastic Communist!"