If you do maybe you can help me

Basically I'm renting a house at the moment, and the lease is coming up to the end of its term but I've not heard from the estate agents. I've tried ringing them a few times but the phone rings out and there is no answer phone, but they've always been a pain in the ass to get hold of

What my question is really is do they have to let me know in writing that come the end of the lease they'll be expecting me to move out or if the lease lapses to I have to get my sorry ass outta there?

any advice is much much appreciated,

Ta

Spud