in 1917, during world war i, british forces drove out the ottomans from palestine and in 1920, the british mandate of palestine was established. in the 1922 british census, al-birwa had a population of 807, consisting of 735 muslims and 72 christians. the christians were mostly orthodox with five anglicans. by the 1931 census, the population had increased to 996, of which 884 were muslims and 92 were christians, living in a total of 224 houses. cement roofs became widely used in al-birwa in the 1930s, during a time of significant expansion in the village.