Sorry for the newbie question, but I have just bought a Ford KA 2003 model, which only has one key with it with a piece of red plastic on the top.

What is the cheapest way to get an extra key which can start the ignition and also one to keep in the house, that just opens the doors / boot please?

Many thanks in advance

John

You need one of these, get the key cut and programmed by an Auto Locksmith.
It has the correct immobiliser transponder chip fitted which will need coding to the car.

[url="http://www.ebay.co.uk/itm/FORD-RED-BLANK-COMPATABLE-TRANSPONDER-TIBBE-KEY-/250777941532?pt=UK_Car_Accessories_Safety_Security&hash=item3a6387b61c"]http://www.ebay.co.uk/itm/FORD-RED-BLANK-COMPATABLE-TRANSPONDER-TIBBE-KEY-/250777941532?pt=UK_Car_Accessories_Safety_Security&hash=item3a6387b61c[/url]

If you had two keys then you can programme spares yourself but as you only have one key then the new one needs to be programmed to your car by the locksmith.
I recommend getting quotes from Locksmiths as cutting/programming costs do vary widely and some may charge extortionate amounts.
Ford may seem like the best option but will likely charge you about £200 - £300 for the pleasure, you can ring your local dealer for a quote but be prepared for a shock.