Sheikh Abubakar Shariff Ahmed is believed to have recruited hundreds of Brits - including Lewthwaite, her pal Jermaine Grant, who is on trial accused of bomb plots, and Lee Rigby's killer Michael Adebolajo.
But Ahmed also known as Makaburi, meaning "graveyard" – was gunned down in Mombasa, Kenya, on Tuesday, just moments after he appeared in public to support five youths accused of being part of the terror group al-Shabaab.
Today we can also reveal how the hate preacher exclusively spoke to the Mirror last year and predicted his own death at the hands of the Kenyan government.
Intelligence sources fear mum-of-four Lewthwaite also blames the Kenyan authorities for the death of her mentor and will retaliate with attacks on Western targets across Africa.
A senior security source said:
"International security services areon high alert after this latest bloody development.
Makaburi was always believed to be at the very top of the hierarchy of terror organisation al-Shabaab.