Industrial firefighting foams are an essential part of on-site safety in UK factories. But for decades some of these familiar canisters contained potentially dangerous, toxic chemicals.

File on 4 Investigates discovers that 3M the multi-billion dollar chemical company responsible for producing the chemicals knew about the risks as early as the 1960s because their own internal studies on animals and tests on workers indicated a possible increase in rates of cancer. Despite this, the company failed to warn its workers of the dangers associated with using the foams for decades and was involved in an environmental accident at one of its sites that led to the chemicals being released into a Welsh river.

The programme obtained never seen before documents showing the regulator warning the company it thought it had committed an offence but choosing not to prosecute it.

In 2004, with evidence of the risks to the environment of the two specific forever chemicals PFOS and PFOA, a report commissioned by the government recommended any remaining firefighting foams containing the chemicals be incinerated. But we discover in the years after that companies struggled to dispose of legacy stock of foams, and, appearing unaware of the unofficial advice, discharged them straight into the sewer with no treatment, in one case with permission from the water company.

3M said that the health and safety of its workers and their families were “critical priorities" for the company.

Reporter: Esme Stallard

Anne Dyer is a trailblazer - becoming the first female Bishop in the Scottish Episcopal Church when she was appointed more than seven years ago. But since then, accusations of bullying and misconduct have dominated her period in charge - even for a time leading to her suspension and calls for her resignation.

Bishop Dyer denies any wrongdoing, while the church itself acknowledges there are deep wounds within the diocese of Aberdeen and Orkney.

Now File on 4 Investigates has discovered new complaints against the bishop, which she says are "totally without merit".

Reporter: Steve Swann

File on 4 Investigates discovers a world of lies and blame within adoption in the UK. The BBC has conducted the most extensive Freedom of Information request ever into adoptions that have broken down, finding that more than 1,000 adopted children in the UK have returned to care in the past five years. That is much higher than the figure in a recent government report - but the true number is likely to be even larger, as only a third of authorities said they collected this data as standard practice. Some adoptive parents say they’ve been given so little support that they’ve been forced to return their children to the care system.

This programme explores the scale of the crisis as we hear from parents pushed to the limit, a teenager returned to care and a social worker giving a rare view of the system from the inside.

Producer: Ashley Kennedy & Claire Kendall

(Photo: Close-up portrait of couple Verity & Ian standing outdoors. Credit: Brij Patel)

Details of advice and support with adoption are available at www.bbc.co.uk/actionline

Multi cancer detection tests or MCDs can detect many cancers through a simple blood test. Many detect fragments of cancerous DNA that have broken off a tumour and are circulating in the blood. They can often then identify where the cancer may be.

More than 140,000 volunteers took part in the trial and the results will be known next year. If successful, the test may be rolled out further.

File on 4 Investigates looks at how effective such tests are and whether the trial will show it can save lives.

Medical journalist Deb Cohen speaks to one woman whose cancer was found by the test and successfully treated. But she also hears from firefighters in America - where it's available to the public - who say it missed some cancers and some people who got a positive result were found not to have the disease after undergoing diagnostic procedures - a so called false positive.

With many hospitals trusts missing cancer treatment targets, what is the best way forward for the NHS to improve outcomes.

Reporter: Deb Cohen

An ambitious plan to digitalize the courts was meant to remove the need for hundreds of thousands of paper documents. But File on 4 Investigates has discovered an IT system, introduced as part of a £1bn project, has been plagued with technical faults - causing crucial information to go missing, be overwritten, or appear lost.

The government body that runs the courts in England and Wales has now checked hundreds of thousands of benefit and child support appeals to identify if any were affected by missing evidence. But sources say the IT bug was known about for years before action was taken.

Original journalism by Alys Harte.

File on Four explores the risks some gay men are taking by habitually mixing their sex lives with drug use. The practice, known as Chemsex has been on the gay scene for more than a decade. It involves taking illegal and addictive substances like Crystal Meth and GHB.

Presenter: Mobeen Azhar

File on 4 Investigates examines the scale of problem gambling in the armed forces and the devastating impact on those serving, veterans and their families.

A new study seen exclusively by the team reveals nearly half of naval trainees who gambled were at risk of harm. This latest research builds on a growing body of evidence that points to a hidden problem across the forces that’s on the rise.

We ask if the MOD is aware of the challenge and if it’s doing enough to help those in need.

Reporter: Alastair Fee

When journalist Georgie Styles is sent unpublished videos of farm workers in Britain being ‘treated like animals’, she begins to investigate the dark side of our food system.

She uncovers numerous referrals of labour exploitation, and hears allegations of workers living in moldy caravans, being trafficked, verbally abused and forced to urinate in bottles.

Her year-long investigation goes from farm workers to our favourite supermarkets.

With gripping first-person testimony, unheard recordings and new documents, this File on Four documentary makes you think about the food in front of you in a new way.

Presenter: Georgie Styles

Abused For Our Food is a Smoke Trail production for BBC Radio 4 and was produced as part of the Bertha Challenge Fellowship.

A van selling coffee and sandwiches from an office car park doesn’t sound like anything special, but there’s one in Swindon helping to keep young offenders out of custody. It’s part of an approach being deployed across the country trying to prevent young people from reoffending by encouraging a shift in their identity.

The idea is to get to know the young offender, figure out what makes them tick. And then, instead of locking them up, find ways of getting them involved in whatever interests them. Selling tea and coffee from the burger van is where those with a culinary eye can learn new skills and start to feel valued for being part of legitimate endeavours. Similar interventions include social enterprises working in bicycle maintenance, hair and beauty and podcasting.

As the adult prison population has soared in England and Wales, the number of under-18s behind bars has dropped markedly in the past 20 years, from around 3000 to 400. File on 4 Investigates spends time with the Youth Justice Service in Swindon to find out how it rehabilitates young offenders in the local community, and asks if the success of the youth system could hold lessons to address chronic overcrowding problems in adult prisons.

Chris Marston, who presents shows on National Prison Radio and spent 10 months in prison discovers that what’s going on in Swindon is very different from his own experiences of the adult criminal justice system.

Reporter: Chris Marston

Main Image: Presenter Chris Marston in front of the Solid Ground coffee van in Swindon.

Up to 80,000 phones were stolen in London’s streets and transport network in 2024, according to the Metropolitan Police. As File on 4 Investigates discovers, gangs are targeting unlocked phones.

We discover that if a phone is unlocked, criminals may be able to access online banking and cryptocurrency accounts within minutes. We hear from one victim who lost £15,000 from a phone stolen from his pocket, another who lost £40,000 in cryptocurrency and about the financial and emotional cost of trying to recover lost assets.

Adrian Goldberg joins City of London Police as they carry out a series of raids as part of Operation Swipe. They have recovered more than three thousand handsets in the last three months alone.

Reporter: Adrian Goldberg

Have you had your phone snatched? Tell us your story via Your Voice, Your BBC News.

Image credit: PA\City of London Police