Victims of human trafficking are arriving in the UK every day with dreams of a better life – and it's impossible to find all of them at ports as big as Dover.

The 58 people who lost their lives in the back of a lorry while crossing the Channel 20 years ago were among them.

But the reality is even if they had survived the treacherous crossing they would have never experienced the freedoms they were promised.

Justine Currell is the executive director of Unseen UK, a charity helping the victims of modern slavery.

She says for many, dreams of finding fortune on our shores turn into living nightmares of exploitation and abuse.

"Most of the people we speak to do think they are coming for a better life but there are some cases of people being encouraged or ever forced to take the trip.

"Many people look at what happened at Essex and Dover and think they would never put themselves in that situation but if you don't have anything at home you are going to take your chances."

Huge amounts of money are paid by those willing to risk everything to climb into a metal box – one man paid £17,000 for his trip, 24 times his annual salary in China.

"They are told they will have a better life, make more money, have more opportunities and may even be able to support others back home," Ms Currell said, adding: "In some instances families are selling their homes to give their children or themselves a better life."

The 'lucky' ones are released upon arrival but embark on an illegal life devoid of health care or rights.

They must take cash-in-hand from unscrupulous employers and risk being caught and deported at every turn.

Others are sold on and set to work in agriculture, construction or the sex trade.

Ms Currell said: "They will put up with this for many days, weeks, months and even years because they feel there is no way out and they are told by the exploiters that is the case.

"Often the gangs will give them accommodation and transport and then take what they earn as payment. They can't go to the police or seek support because they are scared of what will happen to them.

"Those who speak to us have been told if they speak to the police they will be thrown out of the country, put in prison or will bring shame on their family. They tend to put up with a lot more abuse and exploitation than we would.

"They will get to a situation when they realise they do need help and support and will phone our help line. We can tell them they will be safe but we can never guarantee their immigration status."

Often the prospect of returning to countries where life is even worse means exploited individuals would rather stay here in shocking conditions than go home.

In regard to Essex and Dover Ms Currell said she had "no doubt" that if those who died had reached the UK they would have been exploited as they were "easy pickings" and represented "quick money" for the gangs who had arranged their fateful trips.

And those horrendous incidents are just the ones we are aware of – police and border force estimate human cargo passes through UK ports on a daily basis, the sheer scale of trade making it impossible to stop every vehicle.

"We have to assume that if these lorries were coming in with that amount of people on board that that has happened previously and may continue to happen," said Ms Currell.

In this regard big ports like Dover are particularly vulnerable, those tasked with keeping an eye out for suspicious shipments ultimately attempting to find a very small needle in a very large haystack.

When Perry Wacker drove his lorry off the P&O ferry 20 years ago he was only stopped because the company which owned it was unknown to customs officers and he'd paid for the crossing in cash.

It is impossible to know what would have happened to the 58 bodies had he not been pulled over, or to the two men who were minutes from death when they were dragged from a trailer.

It's equally difficult to determine just how many people are living in slavery or servitude in the UK due to its clandestine nature.

Ms Currell is full of praise for Border Force whose officers recognise the people they find hidden among pallets are victims of exploitation but said in order to get a real grip on the problem we need to start to work on the bigger picture.

This will involve international cooperation which is easier said than done when you factor in the sorts of regimes and nations those trafficked are leaving behind – from eastern Europe, through north Africa and into Asia.

She added: "I would urge the government not to conflate immigration with human trafficking. We need to work harder to make these people's live better and not just think about it through the lens of immigration."

To get the latest updates in ongoing cases, police appeals and criminals put behind bars, click here.