Ketamine was designed as an anaesthetic but its use as a recreational drug is growing fast, particularly among young people. It can have life-changing health consequences, yet the use of the drug increased by 85 per cent between 2023 and 2024. Paul Kenyon investigates the ketamine trade and discovers how tonnes of the drug are able to find their way into the UK undetected.

Reporter: Paul Kenyon

Details of organisations offering support and information with addiction are available at bbc.co.uk/actionline

The market where carbon offsets are bought and sold has been projected to grow and grow, as big companies look to prove they can reach net zero. But where achieving reductions in emissions is impossible or expensive, an alternative is to try and arrange for carbon to be taken out of the atmosphere instead. The markets have thrived on linking buyers of carbon offsets - big firms, and even governments - to development projects in poorer countries, where land and labour for tree planting are cheap.

But can these projects be safely verified and measured? Are local communities being exploited to try and make the maths add up? And can the industry afford to admit when a project is underperforming the expectations according to which carbon credits have been sold?

Investigative reporter Max de Haldevang hears from experts and individuals directly involved in high profile carbon offset projects to find out.

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Producer: Robert Nicholson

A Whistledown production for BBC Radio 4

How did a former British soldier become an international people smuggler? Annabel Deas investigates, taking us deep into the UK's hidden criminal landscape. From BBC Radio 4 - Shadow World: The Smuggler. Listen to the full series now on BBC Sounds.

Nicola Packer went to Chelsea and Westminster Hospital for help after she delivered a 26-week-old foetus in her bathroom. But she was reported to the police - and arrested as she lay in bed recovering from major surgery. She was then escorted to a waiting police van and forced to spend the night in a police cell. File on 4 Investigates hears her story and reveals how, behind the scenes of the investigation, police had serious concerns over her controversial arrest. She believed she was only six weeks pregnant when she took abortion medication during lockdown - but she was prosecuted anyway. Her ordeal lasted nearly half a decade and, she says, it has had life-changing consequences for her. The case has also led to renewed calls from MP's and health professionals for a change in the law.

Reporter: Kate West

The story of Gisele Pelicot shocked the world. For almost a decade, the 72-year-old French grandmother’s husband Dominique secretly sedated her with sleeping pills and anxiety medication and raped her. He invited fifty other men to rape her too - documenting the abuse in thousands of photographs and videos. Dominique Pelicot has been jailed for 20 years. But Gisele is not alone.

One British woman, Kate (not her real name) has told File on 4 Investigates how she confronted the unthinkable – that the man she thought loved her, had been secretly drugging and sexually assaulting her for years. He laced her bedtime cup of tea with medication so he could commit his crimes in secret.

File on 4 investigates hears from the police detective who built the case against Kate’s now ex-husband, and how he almost avoided being brought to justice after the Crown Prosecution Service initially said there wasn’t enough evidence to put him on trial. It was left to Kate to fight the system to get justice – and keep herself safe.

File on 4 Investgates discovers domestic spiking is disturbingly common in cases of domestic abuse. One academic has coined the term ‘chemical control ’ to describe the administration of medication to physically subdue women. Unlike physical violence, spiking may leave no trace and hence go unnoticed by victims, the police, doctors, and social workers.

A new named offence of spiking is soon to be introduced. But with much of the focus still on spiking in settings like bars and clubs, will it address the threat behind closed doors?

Reporter: Jane Deith

If you've been a victim of sexual abuse or violence, details of help and support are available at bbc.co.uk/actionline

Around the UK, a hidden crisis has been growing over the past eight years.

Since the Grenfell Tower fire in 2017, something extraordinary has become clear about many of Britain's high-rise residential buildings. They are nothing like as safe as we had imagined.

In fact, the latest statistics show that more than 5,000 high-rise buildings have faults so serious they pose a risk to life. Clearing this up has quietly become one of the biggest infrastructure challenges of our generation, with a bill totalling £16.6 billion and rising, and a project which could continue for the next 20 years.

Author and housing journalist Peter Apps investigates the building safety crisis through the story of one building which has many of the problems afflicting places across the country.

What is the reality for people living there? Why was it built like this? And with the government's promise of 1.5 million new homes over the next five years, do we risk making the same mistakes again?

Presenter: Peter Apps

A Reduced Listening production for Radio 4

2024 experienced the wettest period since records began and extreme rainfall events are becoming more frequent because of climate change. So what's being done to protect us from flooding - and is it enough? The Government has said it will build 1.5 million new homes by the end of the current parliament - but File on 4 Investigates has discovered that hundreds of thousands of homes have already been built in areas at high risk of flooding. And a measure to protect new properties against flash floods caused by intense rainfall has never been made compulsory - despite being introduced 15 years ago.

Reporter: Adrian Goldberg

Pet ownership has rocketed since the covid pandemic, but so have vet prices. In fact, bills have increased by more than 60% in the last ten years. The Competition and Markets Authority is so concerned about the increases it has a launched an investigation into the industry and is due to reveal its findings this year. Datshiane Navanyagam investigates the pet industry and the corporate takeover of high street vets – talking to whistleblowers about how they feel they're being measured on the amount of money they bring in.

Reporter: Datshiane Navanayagam

Every year the UK produces around 50 million tyres for disposal. They’re supposed to be sent for recycling. Instead, big money is being made by diverting tyres to illegal and dangerous 'pyrolysis' plants they're melted down to extract oil and steel. File on 4 Investigates, together with a team of journalists from Source Material, a not-for-profit group specialising in climate and corruption, follow the tyres from the UK to India using tracking devices. The team discovers just how large scale this largely illicit business has become. Earlier this year, a makeshift pyrolysis plant exploded near Mumbai, killing four people. It had been processing tyres from abroad, almost certainly Europe and the UK. Reporter Paul Kenyon confronts a tyre trader in the north of England who admits to shipping his waste tyres to India for pyrolysis.

Reporter: Paul Kenyon

At least two women are murdered every week in the UK in a domestic abuse situation. Newspapers often call it a crime of passion. ‘He lost control’. But what if that’s not true? What if there was a blueprint that, if recognised, could save a woman’s life?

The Homicide Timeline contains eight stages that track the escalation of a controlling relationship from before a couple even meet right up to homicide. Families often say “I wish I’d known”. This programme will tell them the signs to look out for so that they do know, and can stop it.