I've nicked this information from the website: I have to say that in all my dealings with the consulate they have been absolutely wonderful. Like when I could not find my passport on Christmas Eve when my plane to the UK was due to leave in two hours.....

British Consulate-General:

Visiting address: Koningslaan 44
Postal address: PO Box 75488, 1070 AL AMSTERDAM
Telephone: +31 (0)20 676 4343

Visitors to the Consulate are advised not to bring any baggage. All baggage will be searched. At busy times, those with baggage may be asked to wait until the end of the queue to avoid delays for others. Please do not leave your personal belongings unattended at any time. Please note that firearms, knives, sharp objects, and all electrical devices, including laptops, mobile phones and cameras are strictly prohibited inside the Consulate-General. You will not be allowed entry into the Consulate if carrying these kind of items. We regret that we have no storage facility to hold your laptop, mobile phone, camera, or any other personal item, for you during your visit to the Consulate.

Visa Services:
Visiting hours for visa applications: by appointment only
Fax: +31 (0)20 676 1069
E-mail: visa enquiries

Passport & Consular Services:
Visiting hours: Monday to Friday 0900 - 1200 & 1400 - 1530
Telephone enquiries: Monday to Thursday 0900 – 1200 & 1400 – 1700
Friday 0900 - 1200 & 1400 - 1630
Fax: +31 (0)20 675 8381
E-mail: passport enquiries
other consular enquiries

Duty Officer:
The Duty Officer is available outside normal working hours for emergency services to British Nationals only. All routine consular enquiries should be made during normal office hours to +31 (0)20 676 4343.