The official line so far has been that there was no connection between the London bombings of July 7, 2005, and the failed attacks of July 21, 2005. We’re told the 7/21 bombers were “copycats,” emulating the mass murderers of 7/7.

But here’s a surveillance video showing two of the 7/21 terrorists purchasing materials for their bombs—on July 5, 2005. (UK date format is day/month/year.)

Pretty clearly, this couldn’t have been a copycat attack. The question is whether there was coordination between the two cells, and Occam’s Razor says that’s more likely than the alternative: that this was some kind of cosmic coincidence.

UPDATE at 1/19/07 4:03:04 pm:

ABC’s Blotter had a story last month (the only one I could find) from undisclosed MI5 sources that described connections between 7/7, 7/21, and the thwarted plot to bomb airliners. (Hat tip: Colt.)

ABC News has also exclusively learned, with chilling detail, from U.S. and British law enforcement sources that investigators from New Scotland Yard and the British domestic security service MI5 have put together physical evidence and a pattern of interlocking relationships between alleged terrorists that appear to establish a firm link among the subway and bus bombs that killed 52 Londoners on July 7, 2005, a failed set of bombings on July 21, 2005 and a plot to blow up between six and nine airliners, killing as many as 5,000 persons headed to the United States this summer, all the result of three years of planning by British al Qaeda.

Each cell appears to have had ties back to the same British citizen who controlled the plotters from Pakistan and whose identity was first reported by the ABC News Investigative Unit, sources said. That link plus forensic evidence and evidence of overlapping knowledge and personnel in each of the plots is more terrifying to authorities than the prior theory of independent cells operating without knowledge of each others’ plans, sources said.

Intelligence sources also say it points to an organized group of cells working to cause carnage and damage to Britain’s economy, apparently in an effort to wear down the public will to fight along side the United States in the War on Terror.