SCHOOLS face a recruitment crisis if support staff are not given a big pay rise, unions say. School administrators, nursery workers, classroom assistants and school caretakers told a national survey of local government workers hat they were underpaid.The union UNISON has put in a claim for a 5 per cent pay rise and a minimum hourly rate of pound;5. Employers have offered 3 per cent, which will add pound;390 million to local authorities’ wage bills.