Renault Clio oil light and stop displayed

try a oil and filter change using the recomended oil check or replace the oil pressure switch then you might be looking at an oil pump issue you could also try some engine flush

thanks creeder - when I take the oil cap off it is very sludgy - does this indicate any other problems?

it can often be a warning of a head gasket problem but if you have no oil in the water etc it is probaly down to condensation that builds up if you only go short distances. get your oil light sorted then try and give it some regular longer runs