As above, don't drive with a Red light coming on!
It could be the oil pick up pipe - well known problem on these cars. 2 -4 hrs to do depending on how quick you are. About £100 for new pipe, gasket, sealant, oil and filter.
When was the oil and filter last changed? Is the oil old and really thin? Is it 504/507 spec? Filter not changed and partially blocked?
If you can do the job yourself or get it done, I'd start with an oil and filter change. DO NOT use engine flush, it seems to release the built up crap into the system and further block the pick up pipe. (others may disagree!).