The two numbers in the database are both not recognised:
Switchboard: 0191 2860980
Flight information (hold for customer services): 0191 2143334
This page says lost property is "0870 122 1488 ext 3367". Obviously the 0870 number has now been replaced with the 0871 one, but putting the extension number on the end of the 0191 214 prefix gets us through to airport security.
Quite a few web pages give 0191 286 0966 followed by extension number, but this is also not recognised.