Emergency (police, fire, ambulance): 999 or 112
Non-emergency police: 101
NHS non-emergency health advice: 111 (free, 24/7, interpreters available)
Nearest hospital/A&E: Search "A&E near me" on Google Maps. Major central London A&E departments: St Thomas' (Westminster), UCH (Euston), St Mary's (Paddington).
Embassy contacts: Keep your embassy's London contact details saved on your phone.