The chorus of discontent was growing last night over the US use of British airports as staging posts for transporting weapons to Israel.
Aviation chiefs are investigating whether two chartered flights carrying bunkerbusting bombs were properly authorised to stop over at Glasgow Prestwick.
Foreign Secretary Margaret Beckett has insisted she is "not happy" and will lodge a formal complaint if the hazardous material protocol failure is proved - raising speculation of a rift in the Transatlantic 'special relationship'. She has already contacted counterpart Condoleezza Rice to voice her displeasure, while the White House has sought to play the issue down as a "paperwork question".
But calls for a blanket ban on the US using UK territory when transporting arms to Israel were increasing in volume, with critics blasting the Government's "monumental hypocrisy" in asking Hezbollah to give up their weapons.
The embarrassing controversy is currently threatening to overshadow Tony Blair's arrival in Washington today for talks with President George Bush concerning the deteriorating situation in Lebanon.
Liberal Democrat foreign affairs spokesman Michael Moore has written to Mrs Beckett requesting an "urgent review" of US flights.
"In light of Israel's disproportionate military attacks against civilians and the civilian infrastructure in Lebanon and Gaza, in contravention of international law, the Foreign Secretary is right to be angered that the US is supplying Israel with high-tech weaponry via the UK," he said. "What is now so urgently needed is a review of the transhipment of arms through Britain and action to prevent any further such transfers to Israel."
A former British diplomat, who quit as ambassador to Uzbekistan after alleging human rights abuses, said the UK was losing "all credibility with the Arab world".
Craig Murray said: "Whether procedures were followed properly is not the issue. We shouldn't be allowing bombs through our airports to fan this horrendous conflict. This underlines the monumental hypocrisy of the US and Britain. We have been preaching to Iran about arming Hezbollah fighters.
"And all the while we have been arming the Israelis, while resisting calls for an immediate ceasefire."
A motion expressing "extreme concern" about the issue has also been lodged in the Scottish Parliament by MSP Sandra White.
The Foreign Office has made clear that the problem is t he apparent breach of procedure - which has been denied by the US Defence Department - rather than the fact that the flights are taking place.
The US has reportedly lodged requests to bring two more planes through the UK carrying bombs and missiles for Israel in the next two weeks.
Mrs Beckett's comments on the flight protocol are regarded as particularly strong at a time when Britain and America are jointly resisting pressure from other major powers to back an immediate ceasefire.