MI5 also received information in April 2004 from Mohammed Junaid Babar - a former terrorist who became a supergrass - that two men from West Yorkshire called "Ibrahim" and "Zubair" had travelled to a terrorist training camp in Pakistan the previous year.
Witness G was asked why an al-Qaeda supergrass was sent such a bad quality image of Tanweer
Babar was shown surveillance pictures of Khan and Tanweer in August 2004 but failed to identify them, and it was only confirmed after the 7/7 attacks that "Ibrahim" was Khan.
Witness G was asked why a photograph of Tanweer but not one of Khan - known only at the time as "unidentified man E" - was shown to Babar in April 2004.
He replied: "I can only speculate here because we don't know exactly why.
"The judgement we formed was that the cropped photograph of man E was probably such poor quality it wasn't worth showing, but I don't have any contemporaneous record documentation."