I think the first was the Laguna MK2. We had them at work when they first came out - 2001 I think. It wasn't keyless entry but you slotted the card into the dash and pressed a button.

I might be wrong, but I thought the technology used for Keyless Entry/Start and just Keyless Start was very different.

The Keyless Entry type 'key' has an active radio transmitter in the key - which is the sort vulnerable to relay theft where a thief boosts the signal, unlocks the car and drives away when the key is in your front room.

With Keyless Start, the car doesn't even look for the key until it's unlocked by someone pressing the button, and the key itself is normally passive I believe, effectively an RFID tag, though one which can change its code each time it is used to stop someone cloning it. Even when cars had a physical key, the same technology was what was the primary protection stopping the car from starting (and why any car built since the mid 1990s cannot be hot-wired).

Keyless Entry is possibly the most pointless bit of technology ever fitted on a car. People argue that means you can unlock the car without using your hands, but that's no use as you still need your hands to open the door.

Keyless Start is sensible as it avoids having a physical lock barrel in the car, though I wish manufacturers would fit a slot in which to insert the "Key" whilst driving - I hate having it rattle around in the cupholder and if I leave it in my trouser pocket it is uncomfortable.