1999 Renault Laguna Can will not turn over

I have a 1999 laguna dti 1.9 Diesel When I turn the key all the normal lights come on and those that should go out do so but when I go to turn the engine on nothing happens apart from the clock light goes out and there is a faint click been to several repairers but they have been unable to assist with whatever the problem maybe. I despartely require assistance with this matter. I live in the south of England