Tom Watson, Labour's deputy leader, led a delegation of MPs on a trip to Israel this week, saying he wanted to pay respects on behalf of his party at Yad Vashem.
Mr Watson was photographed in Jerusalem laying a wreath at the Hall of Remembrance flanked by fellow MPs Dame Rosie Winterton, Michael Dugher, Ruth Smeeth and Gloria De Piero.
Mr Watson said: "I wanted to come back to Israel and the Palestinian Territories and to pay respects on behalf of the UK Labour Party at Yad Vashem.
"We remembered those who died in the Holocaust and renewed our determination to fight racism and antisemitism - whatever form it takes and wherever it exists.
"We travelled to East Jerusalem to meet inspiring young entrepreneurs from both the Israeli and Palestinian communities studying together."
Mr Watson said meetings with members of the Israeli Labour Party, including its leader Isaac Herzog, were held "to build on our friendships and our determination to work for peace in the Middle East".
The visit was organised by Labour Friends of Israel. An LFI spokeswoman said the meeting with Mr Herzog was "a brilliant evening of discussion and solidarity".
Labour leader Jeremy Corbyn had neglected to take up an offer to visit Israel and Yad Vashem from Mr Herzog earlier this year.
Mr Herzog had sent Mr Corbyn a furious letter after Ken Livingstone's controversial remarks about Adolf Hitler and Zionism.
After suspending Mr Livingstone from the party, Mr Corbyn was invited to Yad Vashem by Mr Herzog.
He did not reply for several weeks and later insisted his diary was full. It is understood Mr Corbyn asked Mr Watson to lead the delegation in his place.
A Labour spokesman said Mr Corbyn would meet Mr Herzog when he visited the UK later this month. But later reports suggested Mr Herzog could not find time in his schedule for the meeting.
The Israeli visit was Mr Watson's first foreign trip as deputy leader. He is a long-standing supporter of LFI and vice-chair of Trade Union Friends of Israel.
Jennifer Gerber, LFI director, told the JC: "It's vital that at a time of growing antisemitism Tom has joined us to visit Yad Vashem as well as meeting a co-existence project that brings Israelis and Palestinians together."
The delegation also met some of the leading lights in Israel's high-tech industry before returning to the UK on Thursday.
Mr Watson will be a guest speaker at the LFI annual lunch in London later this month.