Four primary schools in the U.K. have imposed a ban on fasting for Muslim students during the month of Ramadan, according to the British media.

Barclay Primary School in east London -- one of the four schools that operate under a common foundation called Lion Academy Trust -- informed the parents of the students of the decision in a letter sent last week.

Written by the school's acting head, Aaron Wright, the letter asserted that children were not required to fast during Ramadan under Islamic Law, but were only required to do so "when they become adults".

"Previously, we have had a number of children who became ill and children who fainted or who have been unable to fully access the school curriculum in their attempt to fast," the head also said.

In the letter, the duration of fasting -- 18 hours last year as it is mentioned in the letter -- was described as quite long for a child without sustenance and water.

The Muslim Association of Britain (MAB) condemned the fasting ban.

"We believe that there are sufficient and stringent rules within Islam which allow those who are unable to fast, to break fast," the Mail Online quoted a spokesman of the association as saying.

The Muslim Association of Britain also stressed that this was a decision that should be left up to the parents of the students.

The other three schools that will implement the ban are Sybourn, Thomas Gamuel and Brook House Primary Schools.

There are about 3 million Muslims in the U.K.

The holy month of Ramadan, the ninth of the Islamic lunar calendar, begins Wednesday.