A committee of the London assembly has called for tougher trackside security and improved emergency planning for trains carrying nuclear waste through the capital.

The assembly's Nuclear Waste Trains Investigative Committee has warned that while trains frequently carry spent nuclear fuel through London there has been no London-based training exercise involving all the capital's emergency services.

Assembly members decided to investigate the transport of nuclear waste through London after concerns from residents about the effects of any radiation coming from the trains and about the likely effect of a major accident on the capital.

Spent fuel from three nuclear power stations in the southeast is regularly taken to British Nuclear Fuel's Sellafield plant in Cumbria. The power stations are at Dungeness in Kent, Bradwell in Essex and Sizewell in Suffolk.

While the exact routes through London are not revealed, the trains pass through a number of London boroughs including West Hampstead, Islington, Hackney and Newham in north London and Hammersmith and Fulham, Wandsworth, Lambeth and Bromley in west and south east London.

Due to the lack of appropriate storage facilities at the reactor sites, part loads of nuclear waste are frequently stored at marshalling yards in Willesden, before complete shipments are sent to Sellafield.

Among the report's 22 conclusions and recommendations are that representatives of all emergency services should take place in radiation training exercises, that there should be more proactive monitoring of radiation levels on trains and alongside tracks, that security needs to be improved "as a matter of urgency", and that alternative routes avoiding population centres should be examined.

BNFL had told the committee that the regular transports of nuclear fuel are essential, given the lack storage facilities at the nuclear power plants. Enough spent fuel is generated at each reactor site to fill one transport flask per week, though material is usually stockpiled until two flasks are filled.

While the committee said there was an "unwillingness to give exact figures for the number of transportations of spent nuclear fuel through London annually", it estimated there could be up to 200 separate transportations each year.

Threats including terrorist attacks, vandalism and derailments have also led to the committee calling for an urgent technical review of the risks surrounding the transportation of nuclear waste through London.

Fears over the security of the trains had been raised by the Nuclear Trains Action Group in their evidence to the committee. NTAG, which was set up by the London region of CND in the late 1980s, told committee members that trackside security was very poor. In the wake of the September 11 attacks, the committee concluded that a reassessment of the risks from sabotage or terrorist attack should be carried out.

Darren Johnson of the Green Party, who chaired the committee, said the investigation had examined some important questions to ask on behalf of Londoners.

"We needed to be clear about how prepared London is for an emergency and what potential risks there are for Londoners. The issues raised in this report go beyond London. The question of emergency procedures is a matter of national importance," he said.

BNFL said it had been safely transporting nuclear waste by train for the last forty years. "During that time we have travelled 6 million miles without a single incident or accident. We are very proud of this record and believe it to be second to none," said a spokesman.