Empty room

Possession - Section 8 and Section 21

Hello
I’ve served a section 21 on 1/10 to my tenant who is presently 5 weeks in arrears and has emptied his room apart from a few bits
He refuses to answer questions even though he reads my messages on messenger
He refuses to answer the phone and he is not staying at the property but has the keys still
His second 21 gives notice to leave on Dec 2nd
I will serve a second 8 when he is 8 weeks in arrears which still takes two further weeks to quit
So that will be approx 5 weeks time
If he doesn’t hand his keys back must I then take him to court or can I take the room back.