This week, Greens will go into government in another European country, so why are we not celebrating? The answer is obvious: the Austrian Greens have formed a coalition government with a right-wing party that has odious and sometimes racist policies. So why did the Greens make this decision and what does it tell us about how proportional electoral systems and coalition governments work?

Greens in Austria won an amazing 14 per cent of the vote while the People’s Party won 37.5 per cent. Many on the left, including many Greens themselves, have rightly baulked at the law-and-order agenda that has been pushed through as part of the coalition agreement. Measures include banning girls of 14 and under from wearing headscarves in school, the introduction of preventive custody for individuals assumed to pose a threat to public safety and ensuring people rescued on the high seas are returned to countries outside the EU. Greens have even refused to push for membership of a UN treaty to recognise the rights of migrants to access basic services and be treated humanely.

In spite of these repugnant policies, Austrian Greens overwhelmingly supported entering the coalition, with 93 per cent of Green delegates backing the deal, as a way to prevent another People’s Party coalition with the far-right Freedom Party (FPO). So by forming a coalition with the conservatives, Greens have blocked the fascists from power.

Some policy agreements are also hugely impressive. Greens have managed to swing the government to a pro-European position with the aim of having a positive influence in the EU. The government will agree strict social, environmental and climate conditions for trade agreements. They will block the Mercosur trade deal with Latin American countries, key of which is Brazil where Bolsonaro is encouraging the destruction of the Amazon rainforest. The government has also made a commitment for all young Austrians to travel to Brussels to become familiar with the EU institutions.

But it is on climate and social policy where Greens are set to make the greatest impact. The government plans to: invest €2 billion into local/regional transport; introduce a €3/day Austria-wide public transport ticket; increase taxes on flying; switch the entire power supply to renewables by 2030; fit one million roofs with photovoltaics; and end oil and coal in heating.

There are also plans to reduce wage taxes, introduce a minimum wage for everyone and make the polluter pay through higher taxes on CO2 emissions. Also on the cards is making freedom of information an enforceable right and a requirement that 40 per cent of board members on state-controlled enterprises be women.

Such coalitions may be something that Greens have to learn to live with. As the Green vote surges around Europe, we could see similar coalitions emerging. In Germany Greens look set to overtake the Social Democrats as the main opposition party which could see them form a coalition with the centre-right Christian Democrats.

And here’s the genuine question, one that might well at some point become a real one for Greens in the UK when we achieve PR: if opportunities are presented for Greens to form a coalition to block the far-right, but are nonetheless forced to accept some highly distasteful policies on immigration, while being able to deliver a range of measures to address the climate emergency and create a fairer more equal society, what should they do?

I expect that many of my Green colleagues have an answer that starts with No and ends in Way. But these difficult decisions arise from the absence of a progressive majority, something that is unlikely to be the case in the UK, where the Tories only become the government by exploiting the first-past-the-post system and dividing progressives. A government with just 43 per cent of the vote but an 80-seat majority is able to lurch as far to the right as it pleases.

Had the general election been fought under the d’Hondt PR system used in the European Parliament election – not even the most proportional of systems – the Electoral Reform Society estimates the combined seats of centre-left parties (Labour, Scottish nationalists, Greens and Lib Dems) would have been 330, compared to 298 seats for the Tories and Brexit Party.

The outcome of the Austrian elections, while a triumph for the Greens, makes clear that pragmatism and Realpolitik is needed to block the advances of the far right. It also demonstrates the fragility and weakness of liberal democracy.

Caught between a rock and a hard place, the Greens in Austria have chosen to enter government to keep the far right away from power. Whether this is a dangerous precedent or a noble sacrifice only time will tell.

Molly Scott Cato is Green MEP for the South West of England.