Campbell stunned English football with his transfer across North London.
Revisiting the stunning switch, Campbell told arsenal.com: "It was about two or three months before when Inter Milan were interested. A few other clubs were too - Barcelona came in and I think Bayern came in six or seven months before.
"We (Wenger and Campbell) would meet at night time and it helped because he doesn’t live in a built-up place. It’s not like an inner-city London place where David Dein lived, so it was quite easy to meet.
"I think there were trusted lines. Back then it was a little bit easier to be covert. One of the reasons why is because it wasn't done until late on."
Former Gunners boss Arsene Wenger also said, "We walked together at one o’clock in the morning to talk about (signing)… because he was paranoid it would be discovered.
"This is a transfer we made with David Dein, at his house, and sometimes we had meetings at 11pm so we could make sure no-one could see us. It is an unbelievable story.
“We had an agreement that never came out. Sol definitely knew before the last week (of his contract) that he was signing for us. At least, before that he promised to sign for us.
“I remember his press conference, when I said we will announce a player. Nobody turned up at the training ground. There were only two press people here.
"I will never forget the press’ faces when Sol came in. ‘Sol Campbell from Tottenham’, they couldn’t believe it!"