A campaign demanding that the UK issue a formal apology for supporting the idea of a Jewish state in the Middle East almost a century ago is growing in popularity after the launch of a new parliamentary petition.

Liberal Democrat peer Baroness Jenny Tonge hosted an event at the House of Lords announcing the launch of the Palestinian Return Centre’s (PRC) initiative to pressure the UK government into acknowledging its role in “almost a century of Palestinian suffering” and the UK's wider colonial impact on the region last Tuesday.

If the petition (currently pending approval) reaches more than 100,000 signatures, parliament will have to consider a debate on the subject.

The Balfour Declaration, as it is known, was a 1917 letter from British Foreign Secretary Arthur James Balfour to Lord Rothschild, head of the Zionist Federation of Great Britain and Ireland, promising support for the idea of a Jewish homeland in historical Palestine as long as the civil and religious rights of existing non-Jewish communities were not “prejudiced.”

Britain ended up governing Palestine shortly afterward under mandate rule after the defeat of the Ottoman Empire in WWI.

The controversial meeting in Westminster caused outrage in Israel after video from the event surfaced showing one audience member claiming “If anybody is anti-semitic, it's the Israelis themselves,” going on to say Jews antagonised Adolf Hitler.

Baroness Tonge was criticised for not appearing to challenge the unidentified man. She later said that she did not hear his full “rant”.

Freedom for Palestine's sons comes at a price Show all 2 1 /2 Freedom for Palestine's sons comes at a price Freedom for Palestine's sons comes at a price Qasam al-Razem, right, and the women of his family await the homecoming of his captive son Fouad Quique Kierszenbaum Freedom for Palestine's sons comes at a price Qasam al-Razem, right, and the women of his family await the homecoming of his captive son Fouad Quique Kierszenbaum

The Lib Dems decided to suspend Baroness Tonge pending an investigation into the event, which led her to announce that she has quit the party. The PRC also distanced itself from the comments, which they said were made by a member of the ultra-Orthodox Neturei Karta group.

Palestinian Authority President Mahmoud Abbas joined the chorus in calling on the UK to apologise for the Balfour Declaration ahead of the centenary during a speech at the United Nations in New York last week.

“We ask Great Britain, as we approach 100 years since this infamous declaration, to draw the necessary lessons and to bear its historic, legal, political, material and moral responsibility for the consequences of this declaration, including an apology to the Palestinian people for the catastrophes, misery and injustice this declaration created and to act to rectify these disasters and remedy its consequences, including by the recognition of the state of Palestine,” Mr Abbas said. “This is the least Great Britain can do.”

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The UK’s delegation to the UN did not comment on Mr Abbas’ remarks.

In a statement sent to Al Jazeera, A British Foreign and Commonwealth Office spokesperson said that the government would not apologise for a “historic statement” but recognised that for many, it is a sensitive subject.

“The Balfour Declaration was a historic statement and one that the UK Government will not be apologising for… We are focused on encouraging the Israelis and Palestinians to take steps which bring them closer to peace,” they said, adding that the government supports a two-state solution to the Israeli-Palestinian conflict.