Their messages will be submitted at the British consulate in Jerusalem on Thursday, November 2, 2017, exactly 100 years after Britain promised help in creating a "national home" for the Jewish people in Palestine.
"The main goal is to give these high school students a chance to express themselves about the Balfour Declaration," Sadeq al-Khaddoor, Palestinian Authority Ministry of Education spokesman, told Al Jazeera.
"We want to show that we are able to express our views in a peaceful way, despite the injustice that has happened to our people."
In the correspondence, some children question why that injustice has persisted and say they cannot live in peace like other children across the world. Some ask why the UK does not recognise a Palestinian state, and demand answers as to why the UK will not go back on its Declaration.
The students also express gratitude to Britons who have demonstrated solidarity with the Palestinian people.
One girl from Tubas wrote that her dying grandfather's only wish was that Britain take back its promise.
For supporters of the Zionist cause, the Declaration marked the first milestone leading to the creation of Israel in 1948.
The Declaration was contained in a letter dated November 2, 1917, to leading English Zionist Lord Walter Rothschild from British Foreign Secretary Arthur James Balfour, promising British help in creating a "national home" for the Jewish people in Palestine.
The letter conditioned British assistance on there being no "prejudice" against the rights of existing non-Jewish populations living in the area.
After the defeat of the Ottoman Empire during the first world war, the UK became the dominant power in the region and established Mandate rule in Palestine.
'They're asking that their feelings are respected'
In the letters, some students said that if it were not for the Declaration, their lands today would not be stolen.
"They're asking for there not to be celebrations and that their feelings be respected," said Khaddoor.
Reports said that there are 100,000 letters in total.
Meanwhile, PM May - who leads the ruling Conservative Party - will on Thursday join her Israeli counterpart, Benjamin Netanyahu, at London's Lancaster House for a dinner. The event is not being hosted by the government.
In stark contrast, Labour Party leader Jeremy Corbyn, a lifelong supporter of Palestinian rights, has reportedly declined the invite to the dinner with Netanyahu.
Earlier in October, Palestinians celebrated Corby's refusal to attend a series of events in the UK celebrating the Balfour Declaration.