Hundreds of children with cancer are resorting to inferior treatment because of a failure to open two flagship specialist centres, experts have warned.

NHS officials have admitted that no patient has yet received state-of-the-art proton beam therapy (PBT) at either its new London or Manchester sites, despite a Government pledge to be treating 1,500 a year by 2018.

Leading oncologists have called for transparency after two promised opening dates at The Christie NHS Foundation Trust were missed this year and the deadline quietly pushed back.