The Greens may yet win in Holborn and St Pancras – but what happened to the party set to ‘replace’ Labour? | Andy Beckett

<p>On the eve of the byelection, Polanski’s pledge is to keep the government ‘in check’. It may not be enough to stop a drift back to the political margins</p><p>Only a few months ago, in the spring, there was a sense of giddy possibility about the Greens. Zack Polanski’s radical n