David Cameron uses summit to tackle Argentina's claim on Falklands

A strident David Cameron used the G20 to take Argentina to task yesterday, saying Buenos Aires was setting the "wrong example" by taking protectionist steps that undermined free trade. While he was at it, he took a swipe at France and its plan to introduce a 75 per cent top tax rate.

His toughest criticism was for Argentina, however, and was prompted by the imposition of new foreign currency regulations and the recent nationalisation of an energy company that was mostly owned by the Spanish, YPF. Mr Cameron said "frankly, the G20 should be setting an example" on free trade, not an example on how to undermine it. Late last night, Mr Cameron was also expected to tackle Cristina Fernandez, Argentina's President, over the Falklands. He planned to tell her that she should respect the right to self-determination "not colonialism" of the islanders, who will hold a referendum next year.

As elsewhere Barack Obama and Vladimir Putin attempted to paper over the cracks as they met to discuss Syria, it was clear this was going to be a G20 summit rife with antagonism.

British officials said that while Mr Cameron and Ms Fernandez did not have a formal meeting on the schedule, he would attempt to convey his views in the corridors of the summit. Last week, Ms Fernandez used the obscure "decolonisation" committee at the United Nations to berate Britain for refusing to sit down for negotiations on the Falklands. She said at the UN that she felt "shame from afar" when she saw the Falklands flag raised above Downing Street last Thursday on the occasion of the 30th anniversary of the defeat of Argentina in the Falklands War. She said armed conflicts should not be celebrated or commemorated.

In the speech to a business audience in summit venue Los Cabos, Mr Cameron made bold reference to the YPF nationalisation. "In the last eight months, we've seen just in one country the expropriation of a multinational company, requirements that export revenues in oil, gas and mining sectors be exchanged in local financial institutions, new regulations on foreign exchange assets of residents, insurance companies required to repatriate foreign assets and limits imposed on investment in farmland," Mr Cameron said. "And that's just from one G20 member – Argentina. We have to do better than this. We all know that keeping the world economy open, keeping the trade rules fair, is absolutely vital."

Success or failure? How G20 will be judged

The meeting of the G20 in Los Cabos will certainly be busy. Europe faces a choice between allowing the monetary union experiment it began 25 years ago to come asunder or moving, belatedly, towards the kind of genuine banking and financial union that may prove necessary for it to work properly.

Choosing the latter route will take courage and a little cheerleading from the US, Japan, Russia and everyone else here. But the meeting that really matters is the EU summit in Brussels on 28 and 29 June. This affair in Mexico is about hand wringing and carefully crafted words.

The other show in town was the bilateral meeting between Vladimir Putin and Barack Obama, who will be naturally suspicious of each other while at the same time needing each other. The greatest prize would be bridging their differences to end the violence in Syria. But that remains unlikely.