For supporters of Israel, it was the shot heard around the UK.

Last night, BNP leader Nick Griffin told the entire country on Question Time that the BNP was the only party to support Israel in its war "against the terrorists" during Operation Cast Lead.

This was possibly the worst public relations blow to Israel in this country since Operation Cast Lead itself - or possibly longer. Mr Griffin has just ensured that anyone who supports Israel, or its right to defend itself, will be immediately associated with the BNP. It will take 10 years to shake off.

Clearly, a man who at one point was a Holocaust denier (and has now - he claims - changed his mind, although he refused to explain why because he said he would be prosecuted in France), cannot also be a true friend of Israel.

So why did he do it? Asserting that he is a friend to Israel has two immediate benefits. First, it allows him to argue that he is not antisemitic or racist (the context in which he brought it up last night) - ie it provides him with a convenient cover for other vile views. Second, it makes him appear, to his supporters, anti-Muslim (which in today's UK political climate carried far more benefit than being antisemitic).

For those who have been following the story of Polish MEP Michal Kaminski, the Tory European ally who is accused of holding antisemitic views, Griffin's position last night had particular resonance. Kaminski, after all, is also a staunch public supporter of Israel and its right to defend itself. Last month, he even visited the Jewish state, and paid a visit to the Kotel.

Now, Israel itself has had nothing to do with Griffin (as far as I know), but it has embraced Kaminski. During his visit, he was welcomed by deputy foreign minister Danny Ayalon. He was also guest of honour at the Conservative Friends of Israel lunch at the Tory party conference earlier this month.

How genuine are his views on Israel? Do they come from similar places to Griffin's? And does it really matter?

At the end of the day, the fact remains that this ally of Israel is seen as borderline antisemitic, if not more than that, by many Jews - and by many non-Jews as well, who find the Conservative alliance with him deeply troubling.

Israel's alliance with him is a deep problem for local Jews and indeed anyone fighting racism, because it provides him with just the cover he needs to claim that he cannot possibly be a racist.

Israel might argue that it needs to take its friends where it can find them - and over the years, out of a position of isolation, it has cooperated with and even endorsed many dubious, objectionable and even racist individuals and regimes, such as apartheid South Africa. But this is an extremely short-sighted view. As Griffin's poison embrace last night showed only too clearly, with friends like these, who needs enemies?