I thought this must have been a one-off problem in my block but no, every front door to every Hackney Homes block will swing open and stay open in power cut.
A spokeswoman for Hackney Homes said: "When there is a power failure to a block, the door entry systems are designed to default to open - this is essentially a safety measure in case there is an emergency and residents need to evacuate quickly. Once the power supply is back, the doors revert to normal."
But there are some emergencies involving power cuts where a resident might rather hide behind a locked door. Or where a resident might want to leave their home for a while - preferably with a locked front door.
Think back to the period when banks were going bust. This was when the term "counterparty risk" started doing the rounds. People who thought they'd bought a lump of gold discovered that they had actually bought a piece of paper from a bank saying "I.O.U a lump of gold".
In this case, Hackney residents don't actually have locks on their front doors, they have a note from an electricity supplier saying I.O.U a door lock and a secure home.
Even if your power supplier is reliable this wouldn't be the ideal situation - think riot, flood, earthquake, war, terrorist attack or just long-lasting powercut while you're not in.
Recent discussion about day-long power cuts in Shoreditch: http://shoreditchtriangle.ning.com/
Trader's Power Cut Showdown: http://finsburypark.wordpress.com/2009/01/18/traders-power-cut-showdown/