Ron Prosor, Israel's ambassador to the UN, is one of Israel's most canny and prescient diplomats - as many in London will know from his time as envoy to Britain. It is hard to believe that he had no idea what event he was attending last Thursday, when he joined a luncheon being held in honour of Marine Le Pen, the leader of France's National Front, at the UN headquarters in New York.

French reports have him staying there for 20 minutes, talking to Ms Le Pen on various issues, and a photo of them together was published.

Mr Prosor's version was rather different. He said: "It was an event that I wasn't supposed to be at to begin with, and I got there by accident. When I realised my mistake, I immediately left."

The Foreign Ministry's spokesman in Jerusalem said that Mr Prosor's action was "a fundamental mistake and does not reflect a change in Israeli policy towards the National Front".

There may have been a personal motive for this response. Mr Prosor is probably the best-known professional diplomat in Israel. Many believe he is planning a second career in politics. Perhaps someone at the ministry thought it was about time to remind him that he is still a civil servant.

We can assume Mr Prosor has a basic knowledge of French politics and knew that Ms Le Pen is not entirely mainstream. Perhaps he felt that the National Front has done enough to dissociate itself from its racist past. Either way, this was a highly embarrassing incident for Israel's Foreign Ministry.