By Paul Reynolds
World Affairs correspondent, BBC News website
The technology has killed at least 10 British soldiers
A dispute has developed over a claim by Britain last October that Iran had provided the technology for bomb attacks on British troops in southern Iraq.
Two British newspapers - The Times and The Independent - now say that British officials have dropped the claim.
However, the Foreign Office and the Ministry of Defence say they have made no retraction.
So where does the issue stand?
The original briefing
It all goes back to a briefing given at the Foreign Office on 5 October by a "senior British official". Under the rules of the briefing accepted by those attending, including me, the official's name could not be used.
The official accused Iran - and specifically the Revolutionary Guards - of smuggling the technology across the border into southern Iraq for use by Iran's allies there.
The new technology - employing shaped charges and infra-red triggering - has killed 10 British soldiers in the south of Iraq since May last year. It was first seen in Lebanon where it is used by Hezbollah, which is supported by Iran and Syria.
The official said that the British ambassador in Baghdad had protested to the Iranian ambassador there. Iran has denied that it is in any way responsible for supplying the technology.
The day after the official's accusation was reported, Prime Minister Tony Blair was not quite as specific as the official had been, but he did say that: "The particular nature of those devices leads us either to Iranian elements or to Hezbollah."
The Times story
There the matter stood until 2 January when Michael Evans, the long-serving defence correspondent of The Times, wrote a story based on an eight-day visit to Iraq during the elections in December.
This story stated: "Britain has dropped its allegation that Iran has been supplying extremist groups in southern Iraq with bombs.
"After a thorough assessment of the latest intelligence, military and diplomatic officials have stopped pointing the finger at Tehran, merely saying that the new technology matched bomb-making expertise traditionally found in Syria and Lebanon."
Evans told the BBC News website: "I was briefed by British military and diplomatic sources on my visit to southern Iraq. All downgraded the original claim. They accepted that the technology must have been smuggled into Iraq but they make no accusation as to its origin."
The story was followed by a similar one in The Independent whose headline read: "Fury as Britain admits it was wrong to blame Iran for deaths in Iraq."
The joint statement
The Foreign Office and the Ministry of Defence then issued a joint statement which said: "The article in today's Independent headlined 'Fury as Britain admits it was wrong to blame Iran for deaths in Iraq' is simply wrong.
"The UK Government has always said that the particular nature of the devices leads us either to Iranian elements or to Hezbollah. That remains our position - there has therefore been no U-turn.
"On 6 October 2005 the prime minister commented: 'What is clear is that there have been new explosive devices used not just against British forces but elsewhere in Iraq. The particular nature of those devices leads us either to Iranian elements or to Hezbollah, because they are similar to the devices used by Hezbollah that is funded and supported by Iran... However, we cannot be certain of this at the present time.'
"Although we cannot be sure of this at the present time, we will continue to investigate the matter."
The Independent challenge
The reporter on The Independent story, Kim Sengupta, sent an e-mail to the Ministry of Defence, which he also circulated round the media. This said in part:
"I presume you are aware that on 5 October 2005 William Patey, the British ambassador to Iraq, gave a briefing in London. As a direct result of this the media reported that Britain was accusing Iran of supplying explosive devices used to kill British soldiers in southern Iraq.
"In the reports Mr Patey was referred to as a 'British official' or a 'senior British official'. I was at the briefing.
"The following week I was in Basra when [British General] Jim Dutton went further and accused Iran of running training camps for bombers carrying out attacks in Iraq.
"I have been told subsequently by British sources in Iraq as well as this country that no intelligence link has been established showing that either the Iranian government or the Revolutionary Guard were, in fact, responsible for supplying the explosives.
"Your e-mail appears to suggest that Mr Patey and General Dutton were wrong to point the finger at Iran as the source of the explosives.
"Is it now the MoD's view that Mr Patey and Gen Dutton were wrong in pointing the finger at Iran? In what way is the article in The Independent 'simply wrong'? Perhaps you would care to answer that in the context of what I have detailed as the background to the article instead of simply parroting the prime minister's statement of 6 October as you did in yesterday's e-mail."
It can be seen that the Foreign Office and Ministry of Defence statement ignores the senior official's background briefing of 5 October. Instead it relies on what the prime minister said on the record on 6 October. This was not quite so pointed ("We cannot be certain of this") and so, in the government view, there has been no retraction because there was no detailed allegation, only suspicion.
On the other hand, the "senior British official" did make the accusation and two experienced reporters report that British officers and officials on the ground in Iraq no longer make the claim and therefore, by implication at least, have retracted it.
One final note: Shortly after the original story last October I received an e-mail from a British soldier formerly in southern Iraq. His account is a reminder of the destructive power of the technology in question:
"We were discovering these as early as July 2004 and they were immediately identified as being of Hezbollah origin. Hollow shaped charges, approx paint tin in size and capable of punching through Warrior and Snatch side armour. At the time linked to large anti-personnel device with up to 8,000 ball bearings to go off at the same time. Very nasty stuff. I am not in theatre at the moment but seems the recent successes and prominence in the news are due to the new trigger devices. British forces have always known (suspected) they are smuggled across the border by Iranian special forces to be operated by local militia elements."