Getting keys before completion


Does it break any law if you get the keys before the completion or exchange or it is not that meaningful just a matter of formality?

basically a tenant in situ property is about to complete but the tenant have decided to leave before completion.

the estate agent is quite slacking in responding and i am thinking to avoid any delay in handing over the key as I have the contact with the tenant I am thinking of just for them to hand over the keys to me instead of the estate agent when they leave.

So i will be there inspecting as they are leaving so i get the keys and don’t need to come twice to pick up the keys.

Any suggestion guys?

Its not entirely clear from your post, but I assume youre buying a property with a tenant that is now leaving. The keys on their own dont confer possession, but you have no right to them unless the seller agrees.