The UK and France have announced new measures to prevent "undocumented migrants" entering the Channel Tunnel by tackling the criminals who smuggle them to Calais and across the Channel.
The plans include the creation of a joint police operation aimed at tackling the people-smugglers who profit from the desperation of those trying to reach British shores.
Delays on both sides of the Channel caused by the Calais crisis are costing the Kent economy around £1.5 million a day, the county council estimates.
This figure includes lost revenue to tourist attractions such as Leeds Castle, but not the cost to other authorities such as the police and highways which implement Operation Stack.
Meanwhile, the UK logistics industry is losing around £750,000 a day because of Operation Stack, according to the Freight Transport Association (FTA).
FTA Deputy Chief Executive James Hookham said: "This is the country’s GDP and export standing still in these horrendous queues caused by the situation in Calais."
The operation has been implemented on 24 of the past 40 days, largely due to problems with migrants in France and ferry strikes.
A joint police operation has been launched to target people-smugglers who profit from the desperate migrants trying to reach the UK.
Calais' Mayor has accused Cameron of treating the region with "contempt" - and called on authorities to open the border unless help is given
More fencing and extra sniffer dogs have been sent from the UK to Calais in a bid to curb migrant incursions into Britain.