All schools are expected to provide access to wraparound childcare if there is sufficient demand, either on their own premises or nearby, from 8.00am to 6.00pm to give state school pupils the same opportunities as those in the private sector.
That is not to say that all schools have to provide out of school care themselves, some do, but others out-source the provision.
If schools can demonstrate that there is little or no demand for extended services, they can satisfy the Government requirements merely by signposting to other local provision, such as childminders or nearby out of school clubs.
However, if there is a definite need, schools are required to implement out of school care, but again this does not have to be provided by the school itself. Some schools opt to fulfil the requirements themselves, others invite individuals, playgroups, or other private childcare providers to meet the requirements on their behalf.
It looks like the issue might be that there's insufficient demand at your school
But even at our school where there's after school clubs, it isn't open to every pupil 5 days a week until 6 pm.