The arrangement, which was originally scheduled to be deployed overnight on Sunday but was postponed, will be in place when the M20 reopens at 6 a.m. on Wednesday (December 14). The M20 will be closed from 9 p.m. on Tuesday to 6 a.m. on Wednesday on the London bound M20 between junctions 9-8 and the coastbound M20 between junctions 7-9 while the system is installed. Diversion routes will be clearly marked. Using a contraflow system, Operation Brock aims to keep the M20 open in both directions during peak times. Once the barrier is in place, all HGVs heading to the Port of Dover or the Eurotunnel must follow the signs to Operation Brock at M20 junction 8.   Any EU-bound HGVs that fail to obey signs and attempt to take another route to Eurotunnel or the Port of Dover risk a £300 fine; this includes attempting to bypass the M20 by taking the M2/A2 at Brenley Corner. Police or enforcement agents may also direct them to the back of the line.

All other coast-bound traffic, including local freight and car drivers heading to Europe, should follow the signs and cross over to enter the contraflow on the M20 London bound carriageway. People who intend to use Eurotunnel or the Port of Dover should plan their journeys and check with their travel operator before departing.