The leader of Israel’s Labour movement has called on British supporters of Israel to take a two-pronged approach to their advocacy efforts.

Isaac Herzog, chairman of the Labour Party and leader of the opposition in the Knesset, said tackling the “lunatic” boycott movement was vital.

He also called for an increase in grassroots initiatives to challenge delegitimisation of Israel “all over the UK”, with particular focus on university campuses.

During a visit to Britain in which he met Foreign Secretary William Hague and Labour leader Ed Miliband, Mr Herzog spoke at the Zionist Federation’s annual gala dinner in central London on Sunday.

He praised the ZF’s work but said there were two challenges for advocates to focus on.

“One is to combat Israel hate. Let me say clearly that the BDS movement - while basing itself on errors that sometimes we do - its aim is to abolish the state of Israel.

“We must say it like it is and combat this campaign which is based on ignorance, hate, antisemitism and a major lack of understanding about the conflict.”

Turning his attention to the ongoing peace talks with the Palestinians, Mr Herzog said he feared US Secretary of State John Kerry’s efforts were “moving towards a deadlock” and “crisis”.

The Labour chairman also called on ZF supporters and British Jews to do more to understand the “new structure of Israeli society” and the national debate on greater inclusion of the strictly Orthodox, Arabs and new immigrants.

Those groups needed to be made to feel “part and parcel” of Israeli life, a move which would have a direct bearing on tackling poverty, empowering women and extending Zionist education, he said.

"Israel is much more multicultural than it used to be. We have to offer a vision which encompasses this beautiful mosaic of groups and people - including people with different beliefs and of different denominations.”

In a briefing for journalists arranged by the Bicom advocacy group, Mr Herzog focused on foreign affairs and the West’s response to the crises in Syria and Crimea, and the threat of a nuclear Iran.

He said that while the world looked to Britain for political – and often military – leadership, this country’s international role was now considerably diminished, leaving Britain unlikely to participate directly in military interventions.

“The question is: does the West want to put its foot down and say ‘stop’ here? And if so, by what means? Clearly the Western leadership shows it is reluctant to use force. But what are the alternatives?”

Mr Herzog questioned whether the West would “go all the way” to stop Iran – and said he had asked David Cameron, during his visit to Israel earlier this month, whether Britain still sought a leadership role in world affairs.

The world was moving into a “disturbing” period, similar to that experienced during the Cold War, the Israeli politician suggested.