By Alex Kirby BBC News Online environment correspondent

A UK film-maker says not nearly enough has been done for the victims of the 1986 Chernobyl disaster.

Television Trust for the Environment (TVE) says one of the countries affected, Belarus, has received no international humanitarian aid.

It says although cancers in the affected area are increasing, people are returning there.

And it believes the contamination may stretch much further than officials have acknowledged.

TVE made the film, The Long Road to Recovery, in its Earth Report series, shown on BBC World.

A report by several United Nations agencies last February suggested it might be safe for people to return to many regions affected by radiation from the explosion.

 Click here to watch BBC World and its report on Chernobyl.

Yet the annual thyroid cancer rate among young Belarussians is put at around 1,800. The rate in the UK in under-14s is about seven cases annually.

Tilling poisoned soil

Other cancers, the film says, are on the increase. The UN says they are not the biggest problem, but that psychological factors are causing more distress than the medical effects of radiation.

The radiation limited emergency teams to 40 seconds exposure

It says a dependency culture has grown up, that the original evacuation was on too large a scale, and that the evacuees could return to many contaminated towns and villages.

One sceptical interviewee is Anatoly Kasyanenko, professor of sociology at Gomel University.

He tells TVE: "Sixty per cent of agricultural lands in Belarus are irradiated - and they carry on agricultural production on these lands.

"We know that there are mandatory state controls, but I am very sceptical about these government controls."

Haphazard risk

The official exclusion zone around the nuclear plant extends for a radius of 30 kilometres (18 miles), in an area historically prized for its rich soil.

Checkpoints ring the exclusion zone

The radioactive particles from Chernobyl were carried on the winds, but deposited by the vagaries of the rainfall pattern just after the accident.

TVE says: "Today the pattern of contamination is random - a farmyard may be safe, but at the other end of the barn there could be a 'hot spot' where lethal radiation could make your nose bleed, or worse.

"A 'hot spot' can be as small as the palm of your hand, or as large as 30 sq km."

The radioactivity is seeping into the groundwater, and into plants and the animals which eat them.

Ignoring the hazards

The film says childhood thyroid cancer, lymphatic cancers, heart conditions and poor eyesight have "dramatically increased - and there is a noticeable decrease in the IQ of children".

Belarus children "face growing risks"

The collapse of the Soviet system of controlled food standards, TVE says, meant Belarus and the other countries affected, Russia and Ukraine, were left unprotected against eating contaminated food.

In Belarus some old people have already returned to live in their villages in the contaminated zone. Medical workers sent to check their health will stay only a couple of hours.

And TVE says, despite the widespread belief that the disaster affected only the Gomel region, there are suggestions the contamination could stretch almost to the Polish border.

International pariah

Brest has seen "a marked increase in childhood cancers, particularly thyroid cancer, and cancers in women".

Yet Belarus, it says, has received not a penny of international humanitarian aid, except from children's charities, because it is seen as "the last bastion of a Soviet-style authoritarian state".

TVE concludes: "Chernobyl is a colossal cross-border catastrophe that is still waiting to be addressed.

"And in this new climate of terrorism and possibly nuclear terrorism, the time [to act] is now. Another Chernobyl is no longer a remote possibility."