The most important number to remember in case of an emergency is 112 (It would be wise to save this in your mobile phone). This number can be called for free in any kind of serious emergency (to request the police, fire service or an ambulance) and they will be able to help you in English.

Police, Ambulance, Fire (Emergency)    112

National Police (non-emergency)            0900 8844
Outage Gas, Electricity                            0800 9009
Sea Rescue / Coast Guard (Kustwacht)    0900 0111
Breakdown Service (Car) (ANWB)*            088 2692 888
* This may require a subscription.

On the first Monday of every month at 12.00 noon emergency sirens are tested nationwide. Do not be alarmed. In the event of hearing the emergency siren at any other time, turn on your television or radio and tune in to a local station for further information.

The Dutch Government has produced a brochure in English of what to do in case of an emergency.

If you want more helpful telephone numbers and internet contacts, see here