Shadow Foreign Secretary Douglas Alexander hit the nail squarely on the head in his speech to Labour Friends of Israel this week. Tackling the boycotters within his own party, he made clear that "now is the time to deepen, not weaken" economic and cultural links with Israel. Quite so. There is a strain within the left which flirts with downright antisemitism and which thinks it is being clever couching it with supposed anti-Zionism. But it fools no one.

Mr Alexander deserves credit for his blunt words to those people, pointing out that "the boundary between legitimate criticism of Israeli government policy gives way to some of the worst and most familiar kinds of antisemitism." Clearly there are some boycott supporters who do not think they are being in any way antisemitic. But they are deluding themselves because the boycott movement is, by its very nature, antisemitic - singling out, of all the nations on earth, the Jewish state for boycott.

Labour's leader may not be able to say whether or not he is a Zionist. But its Shadow Foreign Secretary has spoken well.