The unexpectedly early resolution to the dispute between the UK and Iran over the detention of 15 sailors and marines in the Persian Gulf is the direct result of Iran's goodwill and a U-turn by the British government. After initially using threatening language and seeking to add an unnecessary international dimension to the dispute, it eventually opted for direct negotiations with Iran based on mutual respect. This outcome offers a compelling lesson on how to deal with the wider international standoff between the US and Iran.

President Ahmadinejad may have chided the British government at yesterday's press conference for not being brave enough to admit that it had made a mistake by crossing into Iranian waters, but his mood was generous. His "gift to the British people" was with immediate effect, and he asked for no apology or other concessions.

But what was the impediment to immediate recourse to bilateral diplomacy, which could have achieved an agreement soon after the arrest? In 2004, a similar incursion involving British service personnel in Iranian territorial waters was resolved in a matter of days, with guarantees that such incursion would not occur in future.

Tehran has certainly sought similar assurances over the past 13 days, which is reasonable given the long history of British imperial domination in Iran in the 19th century, the US/UK-incited coup of 1953 which overthrew the popular government of Dr Mosaddeq, and the UK's support for Saddam's regime in its eight-year war against Iran, including provision of chemical weapons. Against this background is the current wider context where, in violation of the UN charter, Iran is threatened by the US, UK and Israeli leaders, who regularly assert that "the military option" is on the table.

But Tony Blair effectively dismissed the possibility of a conventional approach by announcing that there would be no negotiations and suspending trade and diplomatic relations. Iran's offer to release Faye Turney was then sabotaged by the British government, which hastily involved the UN security council and the EU, unprecedented in a case which could and should be resolved bilaterally.

The government's heavy-handed approach can only be explained in the context of the US drive for regime change in Iran, which Blair has supported for more than a year. The US and UK, prodded by Israel, have been systematically pursuing a multi-pronged strategy to demonise and isolate Iran, using unfounded allegations that Iran is intent on building nuclear weapons, is directly supporting Iraqi insurgents, and aims to "wipe Israel off the map". With two US aircraft carriers stationed in the area, and a third on its way, there is a sense of deja vu in relation to the period preceding the attack on Iraq, when "evidence", subsequently shown to be false, was used to provide a casus belli.

After over 2,200 hours of inspections, the International Atomic Energy Agency (IAEA) has found absolutely no evidence of a nuclear weaponisation programme in Iran, where Ayatollah Khamenei, the supreme leader, has issued a fatwa against the production, stockpiling and use of nuclear weapons. Yet there are two security council resolutions calling on Iran to suspend its legal enrichment programme and imposing sanctions for its refusal to comply. Strikingly, there is now incontrovertible evidence, provided by Stephen Rademaker, the former US assistant secretary for non-proliferation and international security, that the US coerced the IAEA to vote against Iran in 2005 and, in 2006, to report its nuclear file to the security council.

On another propaganda front, Colonel Justin Masherevski, of the British forces in Basra, announced, on the same day as the sailors' detention, that local sources had told him Iranian agents were providing "sophisticated weaponry" to Iraqi insurgents. Such allegations have been levelled against Iran by the US and Britain since the summer of 2005, but have never been substantiated. Meanwhile, five Iranian diplomats have remained in US detention at an unknown location with no formal charges against them following a raid on their Irbil consulate in January, although Ahmadinejad yesterday denied any link between their plight and the release of the British sailors.

Finally, Ahmadinejad's own call for regime change in Israel - "the occupying Zionist regime of Jerusalem should cease to exist in the page of time" - has been mistranslated and distorted into the notorious phrase, "Israel should be wiped off the map" by the western media. What is never reported is that Ayatollah Khamenei stated unequivocally immediately afterwards that "the Islamic Republic has never threatened and will never threaten any country".

Ahmadinejad's decision to release the British detainees was a sign of strength, and he further stated that he would be willing to reconsider ties with Washington were President Bush to change his behaviour. But the dispute has also highlighted the real dangers of escalation, as happened in 1964 when the Gulf of Tonkin incident was manipulated by the US to justify war in Vietnam.

Yesterday's welcome outcome should show the international community that the solution to the standoff lies in its hands. The UK and other governments must pressure the US to drop its pre-condition of suspension of Iran's legal right to uranium enrichment, and enter into negotiations on all points of conflict.

· Abbas Edalat is professor of computer science and mathematics at Imperial College London, and the founder of the Campaign Against Sanctions and Military Intervention in Iran.

campaign@campaigniran.org