Foreign and Commonwealth Office sources last night confirmed that five British sailors have been detained by the Iranian Navy while sailing a yacht from Bahrain to Dubai.

The sailors were delivering the Kingdom of Bahrain to Dubai, where it was due to take part in an international race. It is thought the yacht was stopped by an Iranian gunboat and boarded last Wednesday, but the FCO issued a statement about the incident only last night, and admitted the boat may have strayed into Iranian territorial waters. It is believed that the FCO had wanted to keep the matter "private" in order to increase the chance of a resolution.

It is understood that negotiations have also been ongoing between Iran and Bahrain, which was a joint partner in the yacht project with the British businessman Andrew Pindar. The five being held in Iran were last night named as Oliver Smith, 31, from Southampton, Oliver Young from Plymouth, Sam Usher, Luke Porter and Dave Bloomer. The first four are all yachtsmen in their mid-20s to early 30s. Mr Bloomer is a Sports DJ for Radio Bahrain, believed to be in his mid-50s.

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The crew members are still in Iran, but all are understood to be safe and well. Last night the Foreign Secretary, David Miliband, said: "FCO [Foreign and Commonwealth Office] officials immediately contacted the Iranian authorities in London and in Tehran on the evening of 25 November, both to seek clarification and to try and resolve the matter swiftly. Our ambassador in Tehran has raised the issue with the Iranian Foreign Ministry and we have discussed the matter with the Iranian embassy in London. I hope this issue will soon be resolved. We will remain in close touch with the Iranian authorities, as well as the [sailors'] families."

An FCO spokesperson confirmed the sailors were from Team Pindar, an independent sailing team which had been due to arrive in Dubai on Thursday for the start of the Dubai-Muscat Offshore Sailing Race. The spokesperson said that negotiations had been made more difficult owing to the Muslim festival of Eid ul-Adha, but that they were hoping things would proceed more swiftly now it was over.

Iranian authorities have said they will make a statement on the detained yachtsmen today.

The race began on Thursday, passing through the shallows of the Arabian Gulf, into the deep waters of the Indian Ocean via the Straits of Hormuz, before finishing two days later in the Bandar Al-Rawdah marina of the Oman capital Muscat.

The most experienced sailor on board, Oliver Smith, completed a degree in Ocean Science and Marine Navigation at the University of Plymouth whilst sailing on the University Mens' 1st Team. He had also spent six months skippering a 50ft survey yacht and doing delivery work in South America and the Caribbean.

Mr Smith's father told the thisisplymouth website: "We're confident this will be resolved very quickly. We're all concerned and the sooner they are released the better. It is dragging along longer than we thought it would do."

The yacht was due to be skippered by Nick Crabtree, an experienced offshore sailor and Team Director of Sail Bahrain, who was not on board when the boat was stopped. According to the Team Pindar website, Bahraini national Sami Kooheji, Captain Peter Gronberg, the managing director of a local shipping company, and two Omani sailors were to crew the yacht for the race.

Team Pindar is owned and named after Andrew Pindar, a Yorkshire businessman who has been supported several British yachting ventures for more than a decade. He sponsored Emma Richards MBE, a British yachtswoman who in 2002-2003 became the first British woman and youngest person to complete the Around Alone, a 29,000 mile, single-handed round-the-world yacht race with stops.

Mr Pindar had recently bought the 60ft Kingdom of Bahrain, and another Volvo 60 racing yacht in Bahrain, in order to support sailing as a way of expanding the sporting interests of the country. His printing company based in Scarborough has commercial links in Bahrain, including printing the state's national examination papers. The detained boat was first launched in 2001, when it took part in the Volvo Ocean Race as part of Team News Corp.

The incident has drawn comparisons with an incident in March 2007 when Iranian authorities captured 15 British service personnel in the same body of water. They were held hostage for 13 days with footage of them broadcast on Iranian television. The Iranian President Mahmoud Ahmadinehjad eventually agreed to pardon them.

Since then, relations between the UK and Iran have become strained further when the UK raised concern over Iran's disputed presidential elections earlier this year and after the Islamic republic announced on Sunday its intention to build 10 further nuclear enrichment plants, to widespread international condemnation.