Handbrake mechanisms - Stuartli
Vauxhall is about to announce that it will modify the handbrakes of around a quarter of a million of its cars, after numerous reports by owners of vehicles suffering handbrake failure when parked.
Handbrake mechanisms - davidh
Its something to do with the ratchet mechanism on the Vectra I believe. If you depress the button and apply the handbrake like you are taught then the hand brake can release enough in the slack "gap" between the notches. They were saying that you should let the handbrake click all the way up then release so the hanbrake is on firmly against the edge of the ratchet and cannot "relax" against the next notch down.

If that makes sense. The Vectra must have little between lee-way between on-and off down to a ratchets width.

They have obvioulsy decided a mods in order rather than giving advice only.
Handbrake mechanisms - Stuartli
A well known consumer magazine and the BBC's Watchdog programme have been running campaigns on the subject for some considerable time.

An expert informed the BBC that he believed it was due to the rachet mechanism and, no doubt, Vauxhall have decided to take some action as a result.