No crank no start need help please

I have a berlingo 2003 1.4I multispace was working 100% 

When I turn the key to on the relay under the bonnet buzzes 

Then when I turn it to start the car the buzzing stops but nothing happens

Then when I let the key return to on the relay starts buzzing again

So in my mind the relay is faulty and that means changing the circuit board but I would like any other suggestions as to what it could be or what could of caused it in the first place. 

Could it be something else that's making the relay do this? 

Thanks in advance