I have changed the bulbs, and the fuse and they're still not working. the sidelights work, headlights etc, but no brakes, no even the large one in the middle of the rear windscreen! please help, I need the car for work tomorrow!

check the brake light switch on it,this is usually what goes bad and causes that to happen,its located up on the brake pedal arm about half way up,this will knock all the brake lights out on it,good luck on it.

above brake pedal there is switch possible its bad

Since you have eliminated the fuse and the bulbs as the problem, all that is left is a broken wire, or the brake light switch. Using a test light, see if voltage it getting to the switch, if it is, replace or adjust the switch as needed.

Hello Julie. It sounds like the brake light switch. If you duck down under steering wheel and look up at the arm the brake pedal is attached to, You should be able to see the switch (it has 2 wires coming from it). You might find one of the wires has come off, they are fitted with push-on connectors. If the wires are intact, pull them off connect them together & switch on the ignition - the brake lights should come on. A replacement switch from a Vauxhall dealer should cost £5-10, but I warn you putting it on means a lot of contortions 'cos of the limited space. Push the drivers seat back as for as it will go to give yourself more room. Good luck!

check the brake light switch normally mounted on the brake pedal bracket the plunger can get stuck and doesn't pop out when you depress the pedal hence no brake lights may just need a squirt of WD40 its gotta be worth a try.