Operation Brock has cost the taxpayer £35 million - even though it was never fully implemented and has now been stood down.
And the final bill will be even higher as the costs do not fully cover the decommissioning of the barrier on the M20 in Kent and returning the London-bound carriage-way to three lanes.
Work on dismantling the barrier between Maidstone and Ashford begins on Monday and will take 16 days to complete, necessitating overnight closures.
The decision to take it down has been broadly welcomed.
However, the costs of the contingency plan may not prove as popular.
Highways England said it was allocated £35m for Operation Brock - a series of measures designed to minimise the impact of a no-deal Brexit.
Of this sum, £30m was assigned for the development and implementation of the infrastructure for the M20 contraflow.
KMTV reported as Operation Brock returned
Another £4m was spent on the design costs and the remaining £26m budget on its implementation.
However, an additional £5m was assigned to adapting the M26 to hold lorries if needed.
Highways England had originally anticipated Brock would be deployed for up to six months, for which costs were being monitored.
Since the contraflow was introduced Brock was activated and deactivated twice.
In October, preparations to fully implementing the scheme - three days before the UK was due to leave the EU - cost £107,000 as 7,500 cones were laid out.
A further £88,000 was then spent deactivating it almost immediately after Boris Johnson sent a letter to the EU requesting the Article 50 deadline be extended to January 31.
It also emerged hotel bills that could run into thousands of pounds were having to be paid to accommodate traffic officers brought in to help manage Operation Brock.
Meanwhile, the government is being urged to renew efforts to find a site for a permanent lorry park after the announcement the contraflow on the M20 is being lifted.