How can i open my petrol cap as its locked up

Take it to the Ford dealer- or maybe FordNut will grace us here with his presence-

Is it the cap or the fuel door that is locked? If it is the fuel door sometimes they have locks that can stick or even the lock cable can break. Your car may have an emergecy release handle for the fuel door in the trunk. Also you can reference your owners manual.

Ectra virgin olive oil worked for me. I'm sure WD-40 would help too, but did n't have any, If you have an eye drop pipette that will help too but again I did n't have one. What I did was covered the key metal in oil, put the key in and ran some extra oil down the key stem into the lock, It took about 5 minutes for the oil to seep into the lock. The next problem is getting a new cap as the key does n't seem to do much when turning it clockwise or anticlockwise. The lock drum maybe worn out. It is polarised for the key but I'm going to search for a generic lock.