What is the law on migrant crossings and how does Priti Patel plan to push back boats in the English Channel?
Boats carrying migrants across the English Channel to England could be turned back towards the continent under new and controversial plans from Home Secretary Priti Patel.
So far this week more than 1,500 people seeking asylum in the UK have attempted to cross the section of water between Dover and Calais, which is one of the world's busiest and most dangerous shipping lanes, adding to the 12,000 or so that have already made the perilous journey this year.
The government has reportedly given the green light to Border Force staff to soon deploy the controversial 'pushback' tactic that is designed to turn craft carrying migrants back towards mainland Europe and French waters.
But the new approach faces huge opposition from human rights and refugee groups as well as the French government, which claims that Priti Patel's latest attempt to tackle the numbers coming ashore, is in breach of international maritime law and is putting the lives of men, women and small children in grave danger.
What is the law?
While the UK has a legal right to protect its borders or carry out work within its waters that may prevent crime, all work by Border Force officials must still comply with international maritime law, which is set out by the United Nations.
There is an international, legal obligation upon everyone out at sea to protect human life where possible and to provide assistance to anyone at sea who may be lost, under an international treaty called the UN Conventions of the Law at Sea, which was signed back in 1982.
The treaty also determines that anyone who finds someone at sea must 'proceed with all possible speed to the rescue of persons in distress'.
But what is less clear, and is currently being debated heavily, is what happens once that person's safety has been established or what the definition of 'rescue' means. Should those found be immediately brought to land or can a boat be turned back, like the Home Secretary is suggesting, if everyone on board is deemed to be safe?
Ben Bano, from Seeking Sanctuary, disagrees with the Home Office's new approach. He said: "The proposal is cruel, dangerous and illegal.
"Are those who put these ideas forward serious about turning around overloaded boats and exposing children and families to yet more danger? And these proposals are a clear breach of our legal obligations."
What would it mean to 'pushback' migrant boats?
Under international law, people have the right to seek asylum in any country they arrive in, but this doesn't have to be the first 'safe' country they reach.
While extremely busy, the stretch of water most migrants choose to cross is a narrow stretch of little more than 20 miles between Kent and the French coast.
With no international waters at that end of the English Channel, most of those leaving northern France find themselves either in French or UK national waters, which are then surrounded by larger and wider search and rescue zones.
If migrants are found in UK waters they are usually brought ashore to a British port where the process of beginning their case for asylum could begin.
But Priti Patel has suggested that Border Force boats should be able to force crafts making their way to the UK to turn back towards France, with some staff already reportedly having undergone the training they require to begin deploying such an approach.
In 2017 Oxfam defined it as “the practice by authorities of preventing people from seeking protection on their territory by forcibly returning them to another country”.
An EU law, called Dublin III, once allowed asylum seekers to be taken back to the first EU member that they were proven to have entered by officials - but this agreement no longer applies in the UK since it has left the European Union, and no alternative has yet been put forward or agreed on.
Why is the tactic so controversial?
The UK government insists it would not be in breach of international law in order to turn back boats in certain circumstances. But many, including aid groups and refugee charities, and perhaps more crucially - the French government - strongly disagree.
In defence of Ms Patel, cabinet minister and culture secretary Oliver Dowden said: “Firstly, in relation to these migrants, it is worth remembering they are coming from a safe country, which is France. This has been a persistent problem for a long period of time. The Home Secretary is rightly exploring every possible avenue to stop that.
“We have said that that will include looking at turning migrants back, but that will only be done in accordance with international law and clearly the safety of migrants is absolutely paramount."
If the tactic was to be deployed - with reports suggesting it is felt to be so controversial it'll require Ms Patel's direct approval with border staff before it is used on each individual occasion - it must be done so only with a boat where officials can be sure they will not endanger life.
But with most migrants travelling on small inflatables very often heavily laden with passengers - that are also having to negotiate much larger ships in the busy Channel - those against the policy say there are unlikely to be times when turning back any boat would not risk placing the people onboard in danger,
There is also concern that any attempts by Border Officials to try and turn back a boat would only result in those onboard choosing to jump into the freezing waters of the Channel, in a desperate attempt to not be sent back to France, and to force a rescue that would enable them to continue their planned journey to the UK.
Among the groups to have hit-out at the policy is Amnesty International UK which says that intercepting boats is 'high risk' and goes against everyone's legal duty to help people at sea.
What about France?
Any boat the UK turns back, arguably has to be re-received by the country that it left, which could pave the way for a very difficult and tense stand-off between UK and French authorities.
Already French interior minister Gérald Darmanin has said his country will not accept the practice of sending back migrant boats.
He said: "France will not accept any practices that go against maritime laws, nor any financial blackmail. The UK must keep to their commitments, which I said clearly to my counterpart Priti Patel.
"The friendship between our two countries deserves better than these actions that harm the cooperation of our services."
French officials are also thought to have been angered by suggestions this week that the Home Office may choose to withhold some of the £55million it promised to France earlier this year to pay for policing and patrols, if officials feel that not enough work is being done to prevent or limit the number of migrant crossings.