The US may have been "led up the garden path" by Britain over a secret deal to allow them to get round a ban on cluster munitions, a former foreign office minister said today.
Labour's Chris Bryant, who steered the UK's ratification of the ban through Parliament last year, insisted the legislation was too tightly drawn to allow any exceptions.
A diplomatic cable among thousands posted on the WikiLeaks website suggested the idea of a "case-by-case temporary storage exception" had the backing of then foreign secretary David Miliband.
It would allow America, for "specific missions", to store cluster munitions on UK territory - such as the Indian Ocean Diego Garcia base - even after the 2013 date set for their final removal.
In the leaked report of a US/UK meeting, Nicolas Pickard, head of the Foreign Office security policy group, is reported as suggesting any deal be kept from MPs in the short term.
"Pickard noted that it would be better for the USG and HMG not to reach final agreement on this temporary agreement understanding until after the CCM ratification process is completed in Parliament, so that they can tell Parliamentarians that they have requested the USG to remove its cluster munitions by 2013, without complicating/muddying the debate by having to indicate that this request is open to exceptions," it said.
Mr Bryant accepted that such negotiations could have taken place at more senior levels than he was privy to but said he had "asked some pretty searching questions" about the issue.
"There are no exceptions allowed for in the way we drafted the Bill. If the Americans are relying on that then they were being led up the garden path by somebody," he said.
"It would be directly in contravention of the Act - someone would be able to take legal action.
"The whole point of signing up to the treaty is that we undertook not only not to use them ourselves but to try to prevent their use by friends and allies."
He expressed doubt that Mr Pickard had been quoted accurately but said it should be looked into and that he should resign if it was the case.
"If a Foreign Office official were to have said that Parliament needed to be circumvented in any shape or form that would be a very serious matter.
"That person would want to be considering their position. But it is a very big if," he said.
"If I were still in Government, I would be wanting to check through all the paperwork to see if there is a British note and if the British note said the same thing."
A Foreign Office spokesman said: "We reject any allegation that the Foreign Office deliberately misled Parliament or failed in our obligation to inform Parliament."
The Cluster Munitions (Prohibitions) Act became law in March, allowing the UK to enforce prohibitions set out in the Oslo Convention on Cluster Munitions.
Implications for the US, which is among countries not to have signed up, were among the most contentious aspects of the British decision to ratify.