Can't switch alarm off

popped to the shops + locked my car as normal using the fob,on return 5 mins later,i can't get the fob to disengage the alarm or open the doors.i was able to get in + start the car ok using my keys + was able to drive home,however,the hazard lights now keep coming on + the red alarm light inside the car is permanently flashing,tried using my spare fob,but it made no difference,any ideas on a solution ?