Iran's seizure of 15 British Navy personnel in Iraqi coastal waters last Friday is a hostile act of war that should be condemned by the UN Security Council and by the North Atlantic Treaty Organization (NATO). It was in addition a clear violation of Iraq's national sovereignty that should draw a firm response from the Maliki administration.

Iran must be warned by London and Washington of the political and military consequences that would result from a failure to immediately release the British prisoners. The Iranians must also be told to stop meddling in Iraq, where to all intents and purposes Tehran is waging a proxy war against US, British and Iraqi forces. There is growing evidence that Iranian factories run by the Revolutionary Guard are producing lethal roadside bombs that are killing British soldiers in southern Iraq, and as well as actively financing and training Shia militias. The Iranians have blood on their hands and must be held to account.

This latest act of aggression by the brutal, erratic and highly dangerous regime of Mahmoud Ahmadinejad must not be tolerated. It also makes a mockery of the idea, popular in diplomatic circles that the United State should negotiate with rogue states such as Iran and Syria in bringing about a peaceful solution to the violence in Iraq. There can be no negotiation with terrorist regimes that actively seek the destabilization of the country, and facilitate the killing of Coalition forces. 
 
Tehran's bold gambit, designed to intimidate the West at a time of heightening tensions over Iran's nuclear program, must result in a greater sense of resolve on the part of the United States and Great Britain, and both powers should escalate the build-up of naval power in the Persian Gulf. The U.S. already has two carrier battle groups in the area, and Britain has several Royal Navy warships operating in the region. The message should be sent loud and clear to Tehran that actions have consequences, and that the West is prepared to use force both to halt Iran's nuclear program and in retaliation for hostile acts against American, British and other Allied forces.

In addition, London and Washington should call for a strengthening of Security Council resolutions against Iran, to include a complete ban on all arms sales to Tehran, as well as a ban on travel for all officials connected to Iran's nuclear program. There will be intense opposition from Moscow and Beijing, both with huge financial and military interests in Iran, but every effort must be made to give the resolutions more teeth.

In conjunction, the United States should refuse to grant the Iranian president a visa to address the United Nations in the coming months. The United States can and must implement a zero tolerance policy for dictators and state sponsors of terror, who should not be given a platform on U.S. soil. Washington should move to isolate the Iranian regime, and deny it the oxygen of publicity on the world stage. U.S. support must also be given to those opposition groups inside Iran working for a free and democratic society.

The European Union, which accounts for 35 percent of Iran's imports, must be pressured into cutting off all financial ties to Iran, with penalties applied to European firms who do business with Tehran. The EU's misguided policy of 'constructive engagement' has been a spectacular failure, and has only strengthened Tehran's position, and bought the Iranians valuable time in building their nuclear program. Countries such as Germany, Italy and France must end the huge export guarantees currently in place protecting their companies trading with Iran. Iran should be closed for business with the West until it ends its nuclear program and support for global terrorism. Decades of European appeasement of Tehran has to be brought to an end if political and economic sanctions are to be effective.

In addition, the Iranian nuclear crisis must be a top priority issue for NATO, and the transatlantic alliance should issue a swift condemnation of Iran's kidnapping of British troops. NATO must also condemn President Ahmadinejad's continuing threats to wipe Israel off the face of the map, and give serious consideration to opening its doors to Israel as a NATO member with a full security guarantee. The Iranians would think twice before launching missile strikes on Tel Aviv if faced with the prospect a war with the world's most powerful alliance. Israel is a vital ally of the West with an extensive history of war-fighting and a first-rate military. Her accession to NATO would significantly enhance the alliance's capabilities, and increase the organization's strategic reach in the Middle East.

Iran must be stopped at all costs from acquiring nuclear capability. If Tehran succeeds in building a nuclear weapon, which it may do within two to five years, there can be no doubt regarding the regime's willingness and intent to use it against Israel or other close U.S. allies. Nor is there any doubt regarding Iran's potential to arm a terrorist organization such as Hezbollah or al Qaeda with nuclear material.

Iran poses the greatest threat to global security of our generation, and the West must be ready to meet the challenge with strength and determination. Not since the rise of Nazi Germany and Communist Russia has the free world been faced with such a grave danger from a state actor. While the use of force is always a last resort, the United States, Great Britain and their allies must be prepared to disarm the Iranian regime if it refuses to back down, with or without the backing of the UN Security Council. To quote a formidable former British Prime Minister, this is no time for the Anglo-American alliance to 'go wobbly', but a time for strength and leadership in the face of barbarism.

Nile Gardiner is director of the Margaret Thatcher Center for Freedom.