The Palestinian ambassador in London has said the British Government’s plans to celebrate the centenary of the Balfour Declaration “rubs salt in the wounds of the Palestinian people,” as would a planned Royal visit to Israel.

In a letter to The Guardian, published on Wednesday, Professor Manuel Hassassian said Theresa May’s Government had “rolled out the red carpet” for Benjamin Netanyahu, while “downgrading” the status of the Palestinian Mission, which was upgraded from a Delegation in 2011.

Hassassian is due to be replaced by another PLO representative imminently, but Palestinian Authority leader Mahmoud Abbas criticised May’s Government for “setting limits and obstacles” in process of granting a diplomatic visa for his replacement, Maen Erekat.

In his letter, Hassassian says 2017 also marks other anniversaries, including “50 years of occupation and 10 years of the siege of Gaza,” and argues that change will only come from international pressure as Abbas now has no more cards to play.

“The window on the two-state solution is closing fast, as Israel grabs more land for its illegal settlements,” he said. “The Palestinians have compromised to a point where they have nothing left to give up. What can Mahmoud Abbas bargain in his forthcoming meeting with Donald Trump?”

Hassassian, who said the peace process since the Oslo Accords had been a “charade,” also criticised the British Government’s strong-arm tactics towards activists seeking to defend Palestinian rights.

“There is hostility towards those who criticise Israeli occupation,” he said. “This was clearly demonstrated in the heavy-handed clampdown on student activities during Israeli Apartheid Week. Equating activism for Palestinian rights with radical Islam, and conflating legitimate criticism of Israeli policies towards the Palestinians with antisemitism, is wrong. The fight for Palestinian rights should not be criminalised.”

In December, May told a meeting of the Conservative Friends of Israel that the Balfour Declaration was “one of the most important letters in history” and that the Government would mark its centenary “with pride”.

However, Hassassian said the Declaration “signed away the Palestinian people’s inheritance and created generations of refugees,” adding that May’s promise “rubs salt in the wound for every Palestinian, as will a royal visit to Israel this year – the first since 1948”.