Manchester's King David High has relaxed a controversial ban on mobile phone use by pupils.

Since its introduction three weeks ago, infuriated parents of offenders have complained that the the six-week confiscation rule has jeopardised their children's safety by leaving them without a phone at evenings and weekends.

Confiscated phones have been returned and confiscation periods of one or a few days will again be the norm.

However, the school maintains that the "over-the-top rule for an over-the-top situation" has achieved the desired result. Action had been taken against 15 pupils, whereas hundreds flouted the previous policy, said governors' chair Joshua Rowe.

"The school has now reported a massive drop in use of mobiles during lessons and a significant increase in attention in classes. Teachers are saying pupils are looking at them and not Twittering under the table."

One angry parent said the school's action had not been thought through, but sympathised with the intention."There are large numbers of BlackBerrys and iPhones with internet access in the school. Kids are being held back by them.

"But you can't take a phone off someone for six weeks. My daughter has got an after-school job and I don't want her out alone without a phone with her."

Another parent contacted the JC after her son's phone was confiscated for sending a text in break time. "I fully support [the rule] if the kids have phones on during lessons - absolutely, take them away. But these kids need their phones for safety."

The school says its zero tolerance policy during school hours will remain in place, with pupils only allowed to use phones at lunchtime or at 3.45pm before extracurricular activities. But parents have been informed that confiscations would now be for a day, although persistent rule breakers would lose them for longer periods.