Just woke up to find a swimming pool in the passenger side footwell of my ford focus 1.4 51 plate. there was heavy rain last night and so its obviously got in some how, no signs of where though, only water i could see was in the footwell.

any help with be fantastic

 

If anything like the early mondeo's, it will be from the POLLEN FILTER housing, ie the bit that stays attached to the car, on the flat section.
Remove it and you will no doubt see the gasket has shrunk and lets in water through the gap.
Reseal with LOCTITE 5910 or 5900, or other decent non(hard) setting sealer.
tabetha