This week's massive leak of confidential documents from the Panamanian law firm, Mossack Fonseca, has given unprecedented access to the way the rich and powerful have used tax havens to hide their wealth. But within the eleven and a half million documents, there is also evidence of how some of the shell companies set up by the firm, or the individuals that owned them, have been the subject of international sanctions and have been used by rogue states and oppressive regimes including North Korea and Syria.

Two months ago a File on 4 investigation into match-fixing in tennis made headlines around the world.

As more and more migrants seek asylum in the UK, is the system for processing their applications reaching breaking point? Allan Urry investigates the impact of a drastic reduction in the numbers of courts hearing cases. At the same time, appeals are going up and key rulings against Home Office decisions to return people to other countries are also piling on the pressure.

Special guardianship orders are a way of giving legal status to those - usually grandparents, aunts and uncles, brothers and sisters - who come forward to care for children when their parents can't. SGOs were designed to let children grow up with family, instead of in care - once a relative is granted special guardianship, the council steps backs and the guardian can raise the child without social services interfering.

It's estimated there are around 620,000 people in England with dementia. Prime minister David Cameron says fighting the disease is a personal priority and doctors in England have been encouraged to proactively identify people with early stage dementia.

The PM says that an early diagnosis allows families to prepare for the care of a relative, but others argue there's no treatment for such a diagnosis and no robust evidence to justify a process that might lead to harm. Deborah Cohen hears from doctors who are concerned the drive to raise diagnosis rates is leading to people being misdiagnosed.

The Government has also pledged millions of pounds to help make England "the best place in the world to undertake research into dementia and other neuro-degenerative diseases". Scientists leading the research say they are making progress to find tests which could identify people at risk from the disease and develop a cure. But other researchers say money is being wasted because current directions in drug development are following the same path as those of the past which have ended in failure.

Producer: Paul Grant.

Are international conflicts creating tensions between Sunni and Shia Muslims in the UK?

Shabnam Mahmood reports from both Sunni and Shia communities and reveals how divisive messages from the Middle East are fuelling intolerance here.

Organisations which monitor hate crimes say sectarian violence, while low level, is increasing.

One Shia man tells the programme: "It is now becoming quite dangerous. It is an attack on me as a Shia that really scares me."

Mahmood reports from one of an increasing number of unity events being staged across the country to foster good relations. A Sunni imam tells her: "These are dangerous times and the religious leadership need to be seen to be doing things to bring communities together."

So can such work prevent tensions escalating in the face of the sectarian propaganda that's increasingly available online and on satellite television channels?

Producer: Sally Chesworth.

The Dutch city of Nijmegen has much in common with the English city of York. Similar in size, both are much visited by tourists because of their histories and architecture. But both also have rivers running through them and are susceptible to flooding. So how do their defences compare? And, as York and other communities continue to mop up the damage caused by the latest catastrophic flooding, did basic mistakes and a failure of planning make a bad situation very much worse?

Vaccination has long been one of the greatest weapons in the battle against a range of potentially fatal diseases. Millions of lives have been saved worldwide, and Britain has played a major role in helping to combat new pandemics. But, rarely, things do go wrong and people develop serious side-effects. In the UK, the Government's Vaccine Damage Payment Scheme is supposed to help those left severely disabled as a result. Among those currently arguing their case are the families of children who developed an incurable and devastating sleep disorder after being immunised against swine flu. But, to date, most have received nothing and Ministers have now gone to the Court of Appeal to try and establish a less generous interpretation of the pay-out rules. Lawyers for the families say the whole scheme is outdated and unfit for purpose. Are they right? Jenny Chryss investigates.

Reporter: Jenny Chryss Producer: Ruth Evans.

File on 4 uncovers the story behind the collapse of one of the biggest health contracts ever put out to tender. Last April an NHS consortium of Cambridge University Hospitals and Cambridgeshire and Peterborough NHS Foundation Trust successfully bid to run older peoples' health services. But in December the £800m, five year contract ended without warning, with local commissioners saying only that it was "no longer financially sustainable." Jane Deith asks what the failure of the Cambridgeshire contract means for the broader policy of trying to improve NHS services by opening massive contracts to competition between Trusts and the private sector.