This article is mainly intended for British subjects although certain elements may also be applicable to nationals of other countries.

Passports are extremely valuable so one must ensure these are kept safe at all times. If this is lost or mislaid, you may experience tremendous inconvenience; do not expect to receive special treatment because you are a foreign visitor.
If loss of the passport is due to your neglect, you must accept the consequences, but do not despair.
Make a note of Embassy contact details for your particular country.
Make photocopies of all passports showing your photograph and passport details from the personal information page, usually at the rear of the document and  keep these safe as they will be just as valuable should the passport be lost/stolen/mislaid etc.
Even a photocopy will contain all vital information and identify your nationality.