April 5 (Reuters) - The 15 British military personnel freed by Iran after a tense two-week stand-off arrived back in Britain on Thursday.

Here is a timeline of the crisis.

March 23 - Iranian forces seize 15 British servicemen, eight Royal Navy sailors and seven marines, in the mouth of the Shatt al-Arab waterway that separates Iran and Iraq, triggering a diplomatic crisis at a time of heightened tensions over Tehran's nuclear ambitions.

March 24 - Britain holds an hour-long meeting with Iran's ambassador in London to demand their immediate release.

-- Iran says sailors have confessed to entering Iranian waters illegally. Britain denies this.

March 25 - Iranian and British foreign ministers talk by phone. March 26 - Iran tells Britain sailors are "fit and well" but does not disclose where they are being held. March 27 - Britain's Prime Minister Tony Blair warns Iran of a "different phase" if it does not free the military personnel.

March 28 - Britain unveils evidence to show that the personnel were captured in Iraqi waters. The incident happened 1.7 nautical miles within Iraqi waters, says Deputy Chief of Defence Staff Vice Admiral Charles Style.

-- The Iranian embassy in London says they were 0.5 km inside Iranian waters.

-- Iran shows footage of captured sailors, publishes letter purportedly from woman sailor saying they had entered Iranian territory. British ministers outraged by video and letter. -- Britain, which earlier froze all official contacts with Iran except those contacts related to the detained crew, says it feared they may have been coerced into appearing on television.

March 29 - Britain says not seeking confrontation with Iran. Tehran suspends release of woman Faye Turney. United Nations issues statement expressing "grave concern". Britain had called for a stronger statement. Iran publishes second Turney letter. March 30 - Iran displays three detained personnel on television and releases a letter from one saying she was being held because of "oppressive" British and U.S. behaviour in Iraq.

-- Blair says the footage heightens people's disgust at their treatment and risks isolating Tehran further.

-- The European Union deplores Iran's seizure and calls for their immediate release.

April 2 - Iran says it wants to resolve the row through diplomacy and says there is no need for a trial.

April 4 - President Ahmadinejad says he will free the 15 as a "gift" but scolds Britain for not being "brave enough" to admit they had made a mistake and strayed into Iranian waters.

April 5 - The 15 British sailors and marines arrive back in Britain.

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