@tausifs
I used to live at UK once, I have faced this situation many times. Our family car once have this situation. No need to worry about. All is to get replacement key. cut it according to your duplicate key. There are several programming techniques for your new keyless remote.
If you google it you will find the right steps.
Its normally like press the remote key and unlock your vehicle, Keep pressing your key open button and put it in steering lock, Switch it to Acc. In next ten seconds your have to press other lock key while led on key remote flashing. Your key is programmed for this vehicle.
Steps on all makes are little different, But process is similar. Its not a rocket science. People in Pakistan might charge you 5000 - 10000Rs only for this trick of programming. You can search it on web. Alternatively you can buy programming instructions for your vehicle on E-Bay. They sell it for 2 - 5 quids , 10 - 15 quids with new remotes.
Have a nice time,