Other Updates;
1825: Reuters reports that the quake has led to the shutdown of roughly one third of Japan's oil refining capacity of 4.5 million barrels per day. More than one fifth of its nuclear capacity, estimated at 49 gigawatts, is also believed to have been cut off.
1823: Our correspondent says there is also growing suspicion that the government and the Tokyo Electric Company (Tepco) are not telling the whole truth about the danger to the public. "We don't trust them," one young mother told him. "They want people to stay calm so they cover up the truth. We are all very afraid she said and we want to find a way to leave the country."
1821: The BBC's Rupert Wingfield-Hayes in Tokyo says there were hundreds of people in the main train station on Wednesday afternoon trying to board bullet trains heading south to Osaka and beyond. "Many were families with young children. They said they wanted to get far away from Tokyo and the radiation danger," he says.
1818: The US Environmental Protection Agency says it is increasing its monitoring of radiation along the western coast and Pacific territories, AP reports. However the US Nuclear Regulatory Commission has said it does not expect harmful levels to reach North America.
1810: The legal exposure limit for the workers was raised on Wednesday from 100 to 250 millisieverts, a move officials said was "unavoidable". Most individuals will absorb 6 millisieverts a year, AP reports.
1809: "I don't know any other way to say it, but this is like suicide fighters in a war." That's how Keiichi Nakagawa, associate professor of the Department of Radiology at the University of Tokyo Hospital, described the 180 workers battling flames at Fukushima.
1806: The British embassy reports that there is still "no real human health issue that people should be concerned about". But the statement continues: "Due to the evolving situation at the Fukushima nuclear facility and potential disruptions to the supply of goods, transport, communications, power and other infrastructure, British nationals in Tokyo and to the north of Tokyo should consider leaving the area."
1803: The UK is advising its citizens to consider leaving northern Japan, Reuters reports.
1759: The embassy says there are "numerous factors in the aftermath of the earthquake and Tsunami, including weather, wind direction and speed, and the nature of the reactor problem that affect the risk of radioactive contamination within this 50 mile (80 km) radius or the possibility of lower-level radioactive materials reaching greater distances."
1757: This is an extract is from the US embassy's advice to its citizens in Japan: "Consistent with the NRC [Nuclear Regulatory Commission] guidelines that apply to such a situation in the United States, we are recommending, as a precaution, that American citizens who live within 50 miles (80 kilometers) of the Fukushima Nuclear Power Plant evacuate the area or to take shelter indoors if safe evacuation is not practical."
1755: Earlier on Wednesday, UK Foreign Secretary William Hague said the team had been sent home because they were not integrated into the wider rescue effort and had not brought their own logistical supplies.
1752: Mr Gray said the fault lay with the embassy. "The Japanese government issued a permit but we needed a letter from the British embassy to get the permit. They said because we weren't part of the British response, we're a non-government organisation, we couldn't have a letter."
1750: The International Rescue Corps has returned to the UK after it was sent back from Japan. Team leader Ray Gray said he was disappointed to be home so soon. "We flew over there with the intention of doing what I thought would have been a good job and a worthwhile job at the request of the Japanese government, and we've spent two days in an airport because we couldn't get a permit to get on the road from the British embassy."
1743: The Swiss foreign ministry said it would lay on charter flights if necessary to bring Swiss nationals home.
1742: Switzerland has also advised that its citizens leave north-east Japan and Tokyo. "At the moment, the development in the damaged nuclear facility is unpredictable and aftershocks are possible," said Swiss president Micheline Calmy-Rey.
1738: The US is advising its citizens living within 80km (50 miles) of Fukushima to evacuate or stay indoors.
1735: The Fukushima plant has a total of six nuclear reactors - all of which have been affected to varying degrees. Our annotated aerial picture shows the layout of the site and outlines what workers are facing at each reactor.
1720: Kyodo reports that the US military is to fly an unmanned plane over Fukushima, equipped with infrared sensors, to give an aerial view of what is going on.
1702: Mr Ellmann tells the BBC World Service that the embassy is taking calls around the clock, "receiving more than 1000 calls a day". A 114-strong French rescue team "is now in Sendai helping the Japanes search and rescue teams", he adds.
1701: France is arranging for extra planes to take their nationals home from Japan on Thursday. Julian Ellmann, spokesman for the embassy in Tokyo, says the advice for French citizens in the capital is "to go the south of Japan, to Kyoto, for example, and for those who want to, come back to France".
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1649: On Tuesday, Mr Oettinger had said Japan was facing an "apocalypse".
1645: A spokeswoman for EU Energy Commissioner Guenther Oettinger has clarified his earlier remarks that "further catastrophic events" were expected. "He just wanted to share his concern and that he was really touched by all the images of people and the victims," said Marlene Holzner. "In this sense, he said that according to we have seen in the media, it seems that in the nuclear power plants at the moment we do not have technical control."
1640: The number of dead is expected to rise. The mayor of Ishinomaki said earlier than 10,000 people were thought to be missing in his town alone and a similar number was given in Minamisanriku.
Etc.
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(^ The Fukushima nuclear power complex)
1837: Gregory Jaczko, head of the US Nuclear Regulatory Commission (NRC) has said there is no water left in the spent fuel pool in reactor four, adding: "We believe that radiation levels are extremely high." Mr Jaczko was speaking to Congress in Washington and it was not immediately clear where his information had come from.
1832: The AP news agency is quoting Tepco as saying a new power line is almost ready which could end the crisis. The disruption of power to the pumps which send coolant through the reactors is what led to their overheating.