The jury in the trial of three men accused of helping the 7 July suicide bombers plan their attack on London has failed to reach a verdict.

They were accused of carrying out a two-day reconnaissance mission prior to the attacks.

Waheed Ali, Sadeer Saleem and Mohammed Shakil visited the London Eye, the Natural History Museum and the London Aquarium while allegedly pinpointing potential targets during the trip seven months before the 2005 atrocity.

The three, from Beeston in Leeds, stood trial charged with conspiring with the four bombers and others unknown to cause explosions between 17 November 2004, and 8 July 2005.

But following the three month trial at Kingston Crown Court, a jury of eight women and four men could not decide on verdicts and were discharged.

The jury had been told that Mr Ali, 25, Mr Saleem, 28, and Mr Shakil, 32, visited a series of locations on December 16 and 17, 2004, which bore a 'striking similarity' to the where the bombs were detonated on 7 July the following year.

Suicide bombers Mohammed Siddique Khan, Shezhad Tanweer, Hasib Hussain and Jermaine Lindsay detonated rucksack devices packed with explosives on three tube trains and a bus killing 52 people and injuring up to 1,000 more on 7 July 2005.

The trial heard that the three defendants travelled from Leeds to London with Hasib Hussain, who later detonated his bomb on the No 30 bus in Tavistock Square claiming 13 lives.

There they met Jermaine Lindsay, who killed 26 people on a Piccadilly Line underground train, and the group stayed overnight in a hostel.

The prosecution alleged that the trip was an essential preparatory step in the plan to bring 'death and destruction to the heart of the UK.'

Movements tracked

Detailed 'cell site analysis' of mobile phone use, including calls to the London Tourist Board and various attractions, allowed the group's movements across London to be mapped.

The three defendants admitted making the visit but claimed it was an entirely innocent social outing and the purpose was for Mr Ali to visit his sister.

They told the jury they used the opportunity to see some of the capital's landmarks at the same time.

All three defendants were close to 7 July ringleader Mohammed Siddique Khan, who killed six travellers at Edgware Road and right-hand man Shezhad Tanweer, the Aldgate bomber who murdered seven others.

The court heard they grew up in the same tight-knit Asian community in Beeston and much of their activities centred on the Iqra bookshop in Leeds of which s Mohammed Siddique Khan, Shezhad Tanweer, Hasib Hussain were all trustees.

Between 2001 and the July 7 bombings in 2005 there were a number of trips organised to training camps in Pakistan, the jury was told.

Following the trip Mr Saleem and Mr Ali also flew to Pakistan where they spent weeks at a camp.

After 7 July two addresses in Leeds were identified as the locations where the majority of the bomb construction and preparation took place.

Traces of Mr Ali's DNA was found on the handle of a small Nike rucksack and on a hat inside it which was recovered from one of the locations.

His fingerprints were also on a chest of drawers inside the second address.

The DNA of Mr aleem, who is asthmatic, was found on an inhaler and further traces found from a blood stain on a pair of martial arts trousers.

A car key for Mr Shakil's Mitsubishi was also discovered in a carrier bag at the first property.

Mr Ali and Mr Shakil were arrested in March 2007 at Manchester Airport as they were about to board a flight to Pakistan. Mr Saleem was detained at his home hours later.

All three defendants made no secret in court of their support for jihad and defending Muslim lands. But they claimed they did not advocate suicide bombings and had no idea about the 7 July plot.