Facebook is facing calls to take concrete action on cyber-bullying after it emerged a scheme it is helping fund to protect children has been forced to push back targets.

Last October Facebook pledged to put $1.3m (£1m) into a programme, run by the Diana Award and Childnet, to help put a “digital safety ambassador” in every British secondary school by October 2019. The plan was for the charities to train pupils to be representatives who could help peers with cyber-bullying.

There were about 2,000 schools involved, with Facebook’s funds to help it reach another 2,500.

The Daily Telegraph has discovered the programme has been implemented in just 461 schools. The date by which it is hoping to be in all British secondaries has been pushed back to March 2020.

It is understood Facebook is concerned the charities will not be able to hit the targets it has set, and is assessing how it can boost numbers.