Costa’s win in Portugal continues comeback by Europe’s centre-left

Analysis: Social democratic parties that have adapted to the political landscape are winning elections again

The unexpected triumph of Antonio Costa's Socialist party in Portugal's elections this week continues a cautious comeback by Europe's centre-left - and, analysts say, may hold some lessons in what remains a mixed picture for the continent's social democrats.

After wins last autumn by Germany's SPD and Norway's Labour party, the Portuguese prime minister's unexpected victory - with 41.7% of the vote, five points up on 2019 - was further good news for a movement that five years ago looked in terminal decline.