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.
Britain has been accused of adopting a "xenophobic response" to the migrant crisis by the UN's special representative on international migration.
Peter Sutherland urged Britain to join the common European approach towards migrants, saying any country that thought it could stop the "alleged floods" of people with fences was "living in cloud cuckoo land".
Mr Sutherland told BBC2's Victoria Derbyshire programme that Britain received a small number of migrants compared to other countries.
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.