UK Car Repair Questions? Ask a Mechanic for Answers ASAP
There's no "easy" way to get to the latch to release it- you have to work from underneath the vehicle, with a flashlight and a long hook and try to catch the lever that releases the latch. If the cable has broken, there is a good chance the latch is binding, rusted, or otherwise hard to move, so this may not work since you are not able to build leverage. Are you sure it is broken at the latch end and not just released from the handle under the dash? Because in that case you can grab it with a pliers or other gripping tool and give it a good pull.