I have a 2003 2.0 auto ford mondeo which keeps blowing a spark plug please can u help thank steven

What is happening to these plugs?

it seems like they just blow or starts to give up, cos we put a new plug in and its fine until it gives up and its always the same one out of the 4

Spark plugs don't "blow". The melt down over time, they crack or they get fouled with something. I suspect yours are getting fouled and you need to find out if it's too much fuel or too weak of spark.

ok thanks. do u think there could be some bigger reason why the engine would keep missfiring then it be fine for a while with new plugs. thanks

Of course there is. That's what I just said The plug is just the damage that is resulting. The engine needs to be diagnosed properly.

ok thanks