LONDON (AP) — A supporter of the Islamic State group who plotted to kill British Prime Minister Theresa May has been sentenced to at least 30 years in prison.

Naa'imur Zakariyah Rahman was convicted last month of planning to bomb the entry gates to the prime minister's residence at 10 Downing Street and then attack May with a knife or gun when she emerged.

The 21-year-old was arrested in November after collecting a backpack he believed was stuffed with explosives. He thought he was getting it from IS adherents, but had been talking to undercover police.

Judge Charles Haddon-Cave sentenced Rahman Friday to life with no chance of parole for 30 years. The judge said Rahman was "a very dangerous individual" and it was hard to predict whether he would ever be de-radicalized.