Click for UK Sepsis Trust guidance for different clinical settings. Scroll down for the Screening and Action tool for under 5s for prehospital care and ambulance services.
References regarding IM benzylpenicillin that Tim mentions:
Harnden A. Parenteral penicillin for children with meningococcal disease before hospital admission: case-control study. BMJ. 2006 Jun 3;332(7553):1295–8.
Hahné SJM, Charlett A, Purcell B, Samuelsson S, Camaroni I, Ehrhard I, et al. Effectiveness of antibiotics given before admission in reducing mortality from meningococcal disease: systematic review. BMJ. 2006 Jun 3;332(7553):1299–303.