Can anyone help - PLEASE!!!?

Hi All,
Just wondered if you could shed any light on my situation. I (like everyone else) am having trouble in starting my 51 reg Clio Expression. When I put the key into the engition, everything is turning on & lighting up as usual, but there is no fire to start the engine. When I turn the key the engine is dead. The immobiliser light seem to be switching off as usual. The battery sign is lighting up, however, I have had 2 new battery's on the car since Feb this year! It does say on my recent MOT advisory notice that the battery is 'unsafe'. Therefore, just wondered if this could be the problem? Like everyone else I am getting really fustrated in going to my car in the morning & having to spend 30 mins TRYING to get it started!

Hope anyone can help.

Thanks