The horrific drownings of dozens of migrants in the Channel yesterday has intensified the diplomatic blame game between the British and French governments.

Further details of how many people capsized near Calais are still unknown, but politicians on both sides of the straits are facing questions about whether the tragedy – and the 25,000 migrants who have arrived on the south coast this year – could have been prevented. Two survivors – one from Iraq and the other Somali – were in a critical condition and being treated for hypothermia in a French hospital.

Boris Johnson – who has spoken to Emmanuel Macron about the disaster – claims he has had “difficulties” in persuading the French to allow Border Force workers to assist the French in detecting smuggling gangs. Britain wants to have officials on the French coast to crack down on the gangs but also process the asylum-seekers.

For his part, France’s Interior Minister, Gérald Darmanin, accused London of “bad immigration management” and has called for renewed cooperation between Britain and the European Union in establishing “safe” routes. The French claim they are doing what they can to handle the crisis and have, since the start of the year, arrested 1,552 smugglers in northern France and broken up 44 smuggler networks.

Home Secretary Priti Patel – under scrutiny for failing to make illegal migration an “infrequent phenomenon” – told the House of Commons there is “no quick fix” and said that “long-term pull factors” must be addressed. Indeed, UK officials have rejected the “safe” routes argument, saying it would prompt more people to make the perilous journey.

Instead, Downing Street hopes that the forthcoming Nationality and Borders Bill will shake up the system by giving residency to those from UNHCR-sponsored programmes.

This proposed new law will bring criminal charges against illegal migrants who will be housed in “reception centres” until they can be deported. Those who enter illegally will also have privileges removed, such as access to a weekly allowance.

The problem with this – and indeed other solutions – is the heavy price to the taxpayer. Take another aspect of the bill, which emulates an approach taken by Australia where asylum seekers are processed in another country.

According to officials, domiciling a single migrant has been calculated to cost over £100,000 – double what it costs in England to lock an inmate up for one year.

There are a number of legal obstacles to the bill too. In the case of offshore proceeding, legal experts have said it would break the 1951 Refugee Convention, claiming the status of a claimant should not be dependent on the mode of entry.

Another proposal is Priti Patel’s controversial “turnback” policy. This would allow the Border Force to intercept boats and redirect them back towards continental Europe. But such a policy could breach international maritime law and has yet to be tested.

The French have a responsibility in responding to the crisis too. France’s Darmanin told Patel earlier this week that officials are pushing through data protection and privacy reforms that would allow surveillance to fly drones to track coastal movements.

Ultimately, long-term solutions can only be achieved when ministers work with France and its allies. The UK and France agreed a £54 million deal in the summer to help patrol the coastline and have promised to “step up” cooperation to ensure the issue is resolved and that another tragedy on this scale does not happen again. That may be hopeful. Despite the drownings, an estimated 40 more migrants made the crossing to Dover from Calais today and have been brought to Dover by the lifeboat charity RNLI.