A tense and angry showdown between bailiffs and residents is expected as scores of families are evicted from the UK's biggest illegal travellers' site.
Bailiffs are expected to arrive at the site at 10am.
Hundreds of residents, bolstered by supporters, have barricaded themselves inside Dale Farm in Basildon, Essex.
They recently lost a decade-long legal fight over unauthorised development on the former scrapyard.
Teams of bailiffs are to arrive at the site to begin forcibly ejecting the travellers.
Essex Police, whose officers will be joined by riot-trained colleagues from all over the country, will attend in strength to try to ensure the eviction is conducted peacefully.
Meanwhile, in London's High Court elderly traveller Mary Flynn will get a final chance to challenge the clearance - but Basildon Council has said the hearing will not delay the start of the operation.
On Sunday night Basildon Council leader Tony Ball said he was worried about the escalation of tensions after protesters apparently called off a last-minute meeting between officials and residents.
Councillor Tony Ball said: "We are very concerned by these latest developments and reports that so-called supporters appear to be calling the shots. We wanted to do everything possible to keep residents updated about the operation and to listen to any concerns and address any final requirements.
"It would appear that we now have no line of communication to the Dale Farm residents. We are very concerned that tension has increased and it may now make our job of clearing the site in a safe and orderly manner even more difficult."
Bailiffs from Constant and Company will have to make their way past reinforced barricades and a newly built wall to keep them out. Half of the six-acre site, which has planning consent, will remain.