Scratching advice please?

[Playitagainsam]

My cat is scratching a certain patch of carpet to the point that he's almost gone all the way through it - and it's thick carpet!!
Does anyone know if there anything I can do about this, or do I just have to live with it? I have no ability to stop him doing anything else so I am not holding out a huge amount of hope! But any thoughts or advice would be very gratefully received.