LONDON, United Kingdom - A former hospital worker was planning to use a homemade bomb to kill "as many nurses as possible" when he was arrested earlier this year, a British court was told on Monday

Mohammed Farooq, 28, was found at a hospital in Leeds, northern England, with a viable pressure cooker bomb, modelled on the explosives used in the deadly 2013 Boston Marathon attack.

But he intended it to be twice as powerful, a prosecutor told a jury at Sheffield Crown Court.

Lawyer Jonathan Sandiford said Farooq "had gone to the hospital to commit a terrorist atrocity and seek his own martyrdom -- first, by detonating the IED (improvised explosive device) and using bladed weapons to kill as many people as possible".

Farooq was a "self-radicalised, lone wolf terrorist" who had also planned to attack Royal Air Force base Menwith Hill, he said.

The defendant visited the base north of Leeds, which is used by the United States, at least twice between January 10 and January 20, Sandiford said.

He later admitted he had made three trips to the base, taking the bomb with him each time, Sandiford said.

Farooq has been charged with preparation of a terrorist act. He has also been charged with possession of an explosive substance and possession of an imitation firearm.

He has denied preparing acts of terrorism or intending to endanger life, but admitted to possessing an explosive device.

The suspect was arrested outside the St James's University Hospital in Leeds in the early hours of January 20 after a patient noticed something "amiss" about him.

Sandiford told the jury the defendant had initially planned to send a bomb threat and then attack those leaving the hospital during the expected evacuation.

But the text message he sent to an off-duty nurse was not seen for almost an hour and the full-scale evacuation did not happen.

The text read: "I have placed a pressure cooker bomb on J28 (ward). It will detonate in one hour. Let's see how many lives you will save."

Sandiford said Farooq left but returned to the hospital shortly afterwards with a new plan to wait in a coffee shop for a staff shift change and detonate his device in order to kill "as many of them as possible".

The explosive material was, he said, was extracted from £600 ($730) worth of fireworks Farooq bought in December last year.

Sandiford said Farooq had also obtained viable instructions for the preparation of "five deadly toxins or nerve agents" -- ricin, sarin, VX, tabun and tetrodoxin.

He said Farooq was self-radicalised through the internet and had constructed the bomb following an article entitled "Build a bomb in the kitchen of your mom" by "AQ chief".

The prosecutor also told the jury that Farooq had a grievance against several of his former colleagues at the hospital and "had been conducting a poison pen campaign against them".