hi guys and girls

have noticed lately that the temp gauge on the mondeo has been taking ruddy ages to go up, usually is up to half way within a couple of minutes, but lately its been taking 5-10 mins to get to half way.

Was in it today, and the gauga went up to half way, as it should, then it went back down to 1/4, then slowly went back up to half way, where it stayed.

Anyone have any ideas as to what could be causing this?

Cheers
Rich