Wrangling which has blocked UK plans to help former Soviet bloc countries prevent nuclear weapons falling into the wrong hands could end this week.
The help programme includes safety at nuclear plants
There have been months of negotiations about the details preventing millions of pounds of cash from the UK and other G8 nations being paid towards nuclear safety in the Russian Federation.
Labour MP Andrew Mackinlay is among those worried by the delays, especially as sending a strong message on weapons proliferation was one of the key reasons why he backed the Iraq war.
He says failing to tackle problems in the Russian Federation could leave open a source where "despots" could get hold of chemical, nuclear or biological weapons.
Foreign Office officials told MPs at the end of last month that agreement in clearing the obstacles was "close". Now the deal is due to be signed on Wednesday.
The UK and other G8 countries pledged help for the Russian Federation at a summit in Canada last year.
British ministers promised £466m over 10 years towards the Co-operative Threat Reduction programme.
In the last two financial years, £28m - from a different £84m budget - has gone to such projects.
Mackinlay says too much time has been wasted
Concerns that the money might be taxed by the Russian authorities have been among the obstacles to the programme.
In the talks, it is understood that when national taxes issues have been addressed, fears about local taxes have become stumbling blocks.
In a written parliamentary answer to Mr Mackinlay in January, Foreign Office Minister Mike O'Brien said: "The continuing absence of either a multilateral or a bilateral agreement constitutes a substantial impediment to expenditure in a number of areas.
"Once we have the agreements in place we will be able to spend project money very quickly.
"In the interim, the UK continues to provide assistance to former Soviet Union countries in a number of areas."
Those areas of help included:
Mr O'Brien said UK officials had taken "every opportunity" to resolve the problems and Tony Blair had raised the issue with Russian President Vladimir Putin last October.
- Safe storage of nuclear submarine fuel in north-west Russia
Nuclear safety work in Kazakhstan
Measures to prevent nuclear weapons expertise spreading from "closed nuclear cities" in Russia
He said many other countries were not able to distribute funds until a legal framework, called the Multilateral Nuclear Environmental Programme for the Russian Federation (MNEPR) is signed.
That programme is due to be signed in Stockholm on Wednesday.
Mr Mackinlay told BBC News Online he was "incredulous" that a deal had not yet been agreed. He has so far not been reassured by officials saying a deal is near.
He suspected there had been "a degree of inertia" on both sides, but asked why Tony Blair had not personally taken up the issue further with Russian President Vladimir Putin.
"We have had 12 wasted years while the West really has not done everything possible," said the MP.
He feared that after the collapse of the Soviet Union, some weapons had been lost onto an "illicit world market place".
Blair and Putin discussed the problems last year
Mr Mackinlay added: "If this money is delivered, it is possible we would at least contain the danger of things going off at reactors and also destroy material that could be illicitly used."
The Russian Foreign Ministry this week told the Russia RIA news agency the MNEPR agreement carried "great significance in Russia".
"This document can in the future be used as a benchmark for drawing up bilateral agreements in the context of the Global Partnership (on threat reduction)", said the ministry.
Since the threat reduction programmes started in the wake of the USSR's collapse, more than 6,000 nuclear weapons have been dismantled.
But a report earlier this year from Washington's Center for Strategic and International Studies, endorsed by 15 influential research centres in a range of countries, warned of the continuing extent of the worldwide arms control problem.
The report, by two former senior arms control experts in the Clinton administration, said the G8 has made major steps but had to do more "urgently" to tackle the "grave proliferation risks" from remaining nuclear, chemical and biological stockpiles.
It said the political will of the G8 nations would determine whether the opportunities promised by last year's treaty were squandered or turned into concrete actions.