The disclosure could leave the Prime Minister open to allegations of deceiving Parliament. Tony Blair promised MPs that they will have a parliamentary debate before the Government gives the go-ahead for a replacement for Britain's Trident nuclear weapon system.

The disclosure could leave the Prime Minister open to allegations of
deceiving Parliament. Tony Blair promised MPs that they will have a
parliamentary debate before the Government gives the go-ahead for a
replacement for Britain's Trident nuclear weapon system.

The Cabinet is to discuss replacing the controversial weapon system
at the end of the year. The Prime Minister has denied that a decision
in principle was taken before the election.

But campaigners at Greenpeace said they had identified the
recruitment of 25 extra scientists at Aldermaston for work on a new
warhead. They are being recruited as part of a massive expansion at
Aldermaston, costing £350m a year over the next three years to build
powerful lasers capable of testing nuclear technology in the
laboratory. AWE chiefs described it as the biggest construction site in
England, and have compared it with the fifth terminal at Heathrow.

From July 2005 - immediately after the last general election - to
March this year, Aldermaston recruited 90 scientists, 250 engineers, 57
technical support staff and 98 business services staff. It now plans to
recruit a further 700 staff by the end of March, 2008.

The Government has repeatedly insisted the extra staff were being
hired to maintain the safety of the existing Trident system, after
reports in The Independent that Downing Street had agreed in principle
to upgrade the weapon. But Greenpeace has a dossier directly
challenging the assurances by the former defence secretary John Reid
and other ministers.

Greenpeace said the most significant finding was that Aldermaston is
recruiting an extra 25 scientists with expertise in hydrodynamics
testing which allows nuclear weapons laboratories to gather test data
previously available only from underground nuclear tests, such as the
one 11 days ago by North Korea. They will bring the total number of
scientists in this field to 90.

"The only real use for hydrodynamic expertise, according to Greg
Mello, the director of the Los Alamos [nuclear plant in the US] Study
Group, is for designing a new weapon," said Greenpeace.

"We are also seeing the increased co-operation between the UK and
the US that might be expected if a nuclear weapon programme was under
way."

This included a doubling in the number of meetings between
Aldermaston scientists and their US counterparts. The MoD has also
appointed a senior US nuclear weapons scientist, Don Cook, to manage
Aldermaston.

Greenpeace said the AWE admitted in 2002 that the capability to
build a successor to Trident would have to be achieved "without
conducting nuclear tests", underlining the need for the specialist
scientists.

The dossier also claims that Cherie Blair's legal chambers, Matrix,
has advised another anti-nuclear group, Peacerights, that the
replacement of Trident "is likely to constitute a breach" of the
nuclear Non-Proliferation Treaty (NPT) which Britain has signed.

"The UK investment programme at Aldermaston is turning the
comprehensive test ban treaty into a hollow shell that allows those
states with advanced technology to develop new nuclear weapons without
nuclear testing," said the report.

The dossier said the NPT would collapse and there would be no legal
restraints on other states such as Iran and North Korea gaining nuclear
weapons if those who had signed it were seen to be breaking it.

It warned that "a state, sooner or later, will actually use a nuclear weapon".