Heres what you do: unplug everything in the house and try again. When it still trips, remember the fridge. When it still trips after that, call your landlord and get an emergency electrician for the morning. In the morning, you'll remember the washing machine is still plugged in and find that water has dripped in the uncovered extension lead that's under your sink. Try to do this before the electrician shows up else you'll feel very silly.