Two of the Madrid terrorists accused of planting bombs on commuter trains on 11 March were in regular contact with their brother in Britain in the months leading up to the atrocities, The Observer can reveal.
Moroccans Rachid and Mohammed Oulad Akcha, who are believed to have blown themselves up with other members of the cell in the police siege of a flat in a Madrid suburb this month, also made a dramatic final call to their brother, Hassan, in Stepney, East London, moments before they committed suicide.
A Spanish police report into Islamic terrorism compiled for the investigation into the bombings revealed that the three brothers were in regular contact before the bombings, although there is no evidence that Hassan was informed of the plot.
A close relative told The Observer that Hassan was picked up by police in London for driving offences just days before the bombings.
Interpol arrest warrants were issued for Rachid, 33, and Mohammed, 28, who went on the run after the atrocity, but it is now thought that they are dead. Spanish police have asked the family to provide DNA samples to help identify the brothers' bodies from the flat. Their sister, Naima, is the only woman charged in connection with the plot and remains in custody in Spain. A fourth brother, Khalid, was also arrested, but released with no charge.
Speaking from his home in Morocco, the father of the Akcha brothers said he had been told by the Moroccan police he was not allowed to talk about his sons.
Security sources said there was no evidence that the bombings were masterminded from Britain, as some reports have claimed. It is thought that there has been irritation in UK security circles about the suggestion that the authorities here were 'blind-sided' by a London connection.
Neighbours have told The Observer that police raided Hassan's ground-floor flat on a council estate on the weekend the cell members blew themselves up. He was last seen driving away from the house with a friend in a people carrier earlier that week and has not been seen since.
Harry Bailey, chairman of the estate's residents' association, said: 'There were all sorts of police with cameras going in and out of the house. They told us there was nothing to worry about.' He said the police had previously visited the flat after tracing an abandoned car to the address.
The UK authorities have confirmed that Hassan was arrested for a passport offence after the bombings, although this was described as 'entirely coincidental'. Spanish police believe the Moroccan was found in possession of a fake Spanish passport.
Details of the calls from the bombers to Hassan first appeared on the Spanish specialist intelligence website El Confidencial, which had obtained documents from the police investigation, this month. They showed that calls from the bombers had been made to a phone line in London registered under Hassan's wife's maiden name.
According to his family, Hassan has been living away from Morocco for at least 15 years. He has been in Britain for six or seven years and married his wife three years ago. The couple moved to their present address six months ago. One relative said he had travelled all over Europe and spent time in Spain.
The relative said he had 'not been himself' since his arrest and had been disturbed by seeing the wanted posters of his brothers on Arab TV channels. 'Of course, he's upset about things. He saw photos of his brothers on Al-Jazeera and Al-Arabiya.'
Immediately after the Madrid bombings, in which nearly 200 people were killed, Metropolitan Police Commissioner Sir John Stevens announced that anti-terrorist police were investigating a British connection.
It is now clear that Stevens was referring to the calls the bombers made to Stepney. Initial Spanish speculation said the police were hunting a radical Islamic cleric called 'Ben Salawi', but there is no trace of anyone operating under that name in Islamist circles in Britain.
British police and intelligence services also believe that Mohammed el-Gerbouzi, a Moroccan Islamic opposition figure based in London, was a 'red herring', and that Moroccan suggestions of his involvement in the Madrid attacks were incorrect.