Brazil is flying high. Having emerged unscathed from the financial crisis, its economy has been growing at 9 per cent a year. Its hugely popular president, Luiz Inácio Lula da Silva, now in his last months in office, seemed set to retire with a chorus of praise – until he plunged into the complications of deep-water oil. Just as Icarus saw his wings of wax melt as he flew too close to the sun, so Mr Lula is risking his legacy as controversies multiply over his petroleum policies.

The April blowout of BP's Macondo well in the Gulf of Mexico dramatised the difficulties of oil exploration in deep waters. The next phase in that drama could come in giant fields recently discovered by Petrobras, Brazil's state-controlled oil company. They lie 7,000 metres below the Atlantic, beneath unstable salt beds up to 2,200m thick, far deeper than the layer of salt capping the Macondo.

These discoveries come with formidable production problems. But they also fed Mr Lula's geopolitical ambitions, while fuelling election fever in the months before his successor is chosen in October. Banned from re-election by the constitution, Mr Lula is using the image of Brazil as a rising oil power as a political weapon, invoking feelings of triumphalism to help his Workers party to victory.