The newspaper said it had obtained FBI documents indicating Hamza, the former imam of London's Finsbury Park mosque, dealt personally with Abu Zubeidah, Osama bin Laden's director of operations.
Zubeidah, a Palestinian now in U.S. custody, communicated bin Laden's instructions and messages from his hideout in Afghanistan to al-Qaida cells around the world.
The Telegraph said Hamza had the power to refer recruits to Zubeidah for "leadership training" in Afghan terror camps. Hamza also reportedly built a relationship with the Taliban foreign minister and sent him a laptop computer for his personal use.
The newspaper said although now removed from his post at the mosque, Hamza continues to address his followers outside the building every Friday.
An attempt to revoke his British citizenship has been delayed, pending appeals that may not be heard for several months.