The Government updated its possession guidance on 27 November to allow for the change from lockdown to tiers but, also very importantly, to make clear was what very muddy about evictions. 

The Christmas truce on evictions which starts on 11 December until 11 January does NOT apply to the "exception" cases. These include ASB cases and those where a possession order has been made due to illegal occupation, false statements, domestic abuse and extreme rent arrears of 9 months or more (discounting arrears after 23 March 2020) etc.

However if you already have a possession order and it is not clear on the face of it which ground was relied on, the bailiffs won't just take your word for it. The landlord has to make an N244 application (albeit no fee payable) and await a hearing for a declaration (that it is an exception case).

Always ensure that your possession orders clearly set out the ground relied upon, especially for example if some grounds were pleaded but not relied upon in the end. 

Do note bailiffs will still cancel an eviction if any household member has the virus, is self-isolating or is clinically extremely vulnerable.