He said: “I remember the exact place, he told me some b******* story about a generator.
“He said that his brother tipped a battery and the generator stopped working. He asked me very kindly.
“He just asked me for a favour.
“I did not want to let him down so I said yes.”
But the witness, who is from the Midlands, said he did not have any money so asked his father to help.
Prosecutor Duncan Penny QC asked him: “Did your father tell you that he was concerned about acid because it can be used to manufacture explosives?”
The witness replied: “Yes, he did.”
He added: “I asked him to buy it. Straight away (he) refused it. He said ‘this is dodgy, don’t buy this online’.”
Asked why, the witness said it was because Hashem was “from Manchester” adding his father was concerned it could be used to make explosives.
The witness said he “100% believed” Hashem’s reason for sourcing the acid, adding: “It wasn’t that I thought he was going to do something dodgy.”
The witness said Hashem had repeatedly tried to contact him by phone and text in the following days.
He said: “I just did not want to. I felt like I let him down.
“I did not want to face him on the phone in case he was disappointed in me because Hashem used to do a lot of favours for me.”
He added: “I did not have a clue this would happen.”
The witness told jurors he first met Hashem at a party in 2015.
He said Hashem initially dressed in western clothes but after he visited Saudi Arabia in 2015 he came back “more religious” and advised his friend to pray more, jurors heard.