How soon can Section 8 be served?

Please could anyone tell me how soon I can serve Section 8?
My tenant has been sacked from their job. Rent is due on 31st December for January, she says she has no money and no means of getting any. Housing benefit will only pay £300-£350 per month max. The flat she is occupying is £600 per month. Her mental healthcare people have basically told her to sit tight in my property. She just laughed and slammed door in my face.
Can I serve Section 8 on the 1st January 2019? and which ground? or do I need to wait longer?
I would be very grateful for any advise.

Hi Tracey, if a tenant isn’t paying the rent and won’t leave the property, then you can use section 8.

We have a full guide to this here.

The quick answer, however, is that the tenant will usually need to be in two months’ worth of arrears for section 8 grounds to exist.

Sam

Thank you for your reply