CONTIGENCY measures costing £80,000 a week start on Monday in a bid to avoid gridlock in Portsmouth.
Planners fear up to 70 per cent of hauliers will arrive at Portsmouth port for EU-bound travel without the correct paper work if Britain leaves the EU without a deal next Friday.
The Brexit date is uncertain as prime minister Boris Johnson bids for an election in December and awaits the EU to grant an exit extension.
Speed limits on the M275 southbound were due to come into force today but were deferred.
But now Portsmouth City Council confirmed the new 40mph limit will be in force from Monday. It will take three nights to change signs and road markings. Northbound traffic is not affected.
Any hauliers travelling from the M3, A34, M25 and A3M will be first directed to the A31 near Winchester to get them ready for the new border.
Once checked - by a team on shift from a pool of 130 people - they will be allowed on to Tipner West.
The new lorry park is no longer being used as a holding area and will instead by used as a rolling checkpoint.
If the A31 is overwhelmed then a 1.8-mile section of the A303 will be used to hold lorries.
Hampshire Local Resilience Forum's Neil Odin, who is chief fire officer at Hampshire Fire and Rescue Service, said: ‘Our role within the LRF is to plan for the reasonable worst-case scenario set out in the Government’s contingency planning assumptions.
‘For many months now, we have been working extremely hard to identify what that is and look at the ways we can mitigate and manage the risks that are likely to arise.
‘Portsmouth International Port’s close proximity to the motorway means there is only capacity for 13 lorries before reaching the main roundabout. Without any contingencies in place to prevent queuing, as our reasonable worst case suggests, this will impact on the road network and beyond.
‘Our focus is to keep the port operating, keep the freight going in and out of the UK and enable the population of Portsmouth and Hampshire South to continue to go about their daily lives.’
So far government has funded around £1.25m of an expected £4m spend on preparations.
Councillor Rob Humby, deputy leader at Hampshire County Council said: ‘Hampshire County Council continues to work closely with our partners in the LRF to ensure we keep Hampshire moving whatever happens on October 31st and beyond.’
He added: ‘Whilst the outcome of the Brexit process remains uncertain, I would like to reassure residents that we are working together to do everything possible to keep traffic flowing and ensure access to supplies and services can continue.’