U.K. Opposition Leader Jeremy Corbyn is a patron of one of the 20 groups on a BDS blacklist whose senior activists will be barred from entering Israel.

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The Palestine Solidarity Campaign, which Corbyn was also once chairman of, was on the list published Sunday by the Strategic Affairs Ministry following months of pressure by Haaretz.

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A joint team from Israel’s strategic affairs and interior ministries determined that those holding senior positions in any of the 20 organizations – including groups in Britain and the United States – will be included in the blacklist. Israel's Strategic Affairs Ministry says exceptions to the blacklist will be made for diplomatic reasons (official positions or state invitations) and on humanitarian grounds.

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Although Corbyn is a veteran pro-Palestinian campaigner, his personal views on the boycott, divestment and sanctions movement are not clear. Despite his ongoing involvement in bodies that expressly support the BDS movement, a spokesman for the Labour leader clarified last December that Corbyn was “not in favour of a comprehensive or blanket boycott.

“He doesn’t support BDS,” the spokesman continued, adding, “He does support targeted action aimed at illegal settlements and occupied territories,” before noting that Corbyn himself would be happy to buy Israeli goods.

Corbyn has made several visits to the Palestinian territories over the years but has never visited Israel (as far as is known). He has also made a number of trips to Palestinian refugee camps in Lebanon and Syria, and in 2014 attended a wreath-laying ceremony at a cemetery in Tunisia where PLO fighters – including one involved in the 1972 Munich Olympics massacre – were buried.

Corbyn has visited the Gaza Strip at least twice, in January 2010 and February 2013.

Immediately after that 2013 visit, he wrote to then-Foreign Secretary William Hague, describing Gaza as “one huge suffering refugee camp.”

In the letter, made public after a Freedom of Information request, Corbyn wrote, “At one of the meetings I attended, I was asked if we would, at the very least, a) stop allowing Israel’s criminal politicians to come to our country freely; b) if we would ensure the BBC portray Palestine fairly; and c) if we would end the siege of Gaza.

“Had I not been working toward all of these three aims. I’d have hung my head in shame,” he added.

Corbyn was criticized in September 2016 for reportedly turning down an invitation by the Israeli Labor Party to visit the Yad Vashem Holocaust memorial in Jerusalem, opting to send a party official instead.

The London-based Palestine Solidarity Campaign is one of the most active pro-Palestinian groups operating in Britain. The movement’s website describes the Labour leader as “tireless in his support for Palestine,” noting that he has taken part in parliamentary delegation visits to Palestine and arranged meetings with U.K. MPs.

Several of these meetings have proved controversial. In May 2012, Corbyn showed a group of the group’s supporters around Parliament, including Tapash Abu Shaim, an activist who has shared numerous conspiracy theories on social media over the years – including that Israel was behind 9/11 and the Charlie Hebdo killings.

Abu Shaim subsequently thanked Corbyn on Twitter for being “the best tour guide,” to which the then-Labour backbencher replied, “It was a pleasure showing PSC supporters round the vagaries of Parliament and British history.”

Despite his reported anti-Semitic views, Abu Shaim was allowed to man the PSC stall at the Labour Party conference last year.

Other U.K.-based groups included in the blacklist are War on Want, a charity that aims to combat “the root causes of global poverty, inequality and injustice,” according to its website, and which also has a major focus on Palestinian issues.

Another is Friends of Al-Aqsa, a charity based in the East Midlands city of Leicester. In August 2016, the Guardian newspaper reported that the group had collected £10,000 for Corbyn’s leadership campaign at a fundraising dinner the previous year.

“Corbyn’s campaign said it did not declare the donation because its bank subsequently rejected the cheque as it was made out to the wrong person. Any donation above 7,500 pounds sterling should be declared to the Electoral Commission,” the newspaper wrote.

Friends of Al-Aqsa founder Ismail Patel has publicly expressed sympathy for Hamas, and his organization was among those organizing the visit of Ra’ad Salah, head of the Northern Branch of the Islamic Movement, to Britain in 2011.

Corbyn was also a supporter of that trip, although Salah was arrested by British police the day before he was due to speak at a public meeting with the then-backbencher.

Sarah Colborn, the then-director of the Palestine Solidarity Campaign – which was also involved in organizing Salah’s visit to Parliament – condemned a “campaign of smears” against him that she said amounted to “an obstruction of the course of justice.”

The following year, Corbyn described Salah as “a very honored citizen” whose “voice must be heard.” However, he has since made clear that he had been unaware of the Islamic preacher’s previous conviction for racist incitement.