"They needed to announce the new England coach in a period that was impossible for me," he told the BBC.
"Also I wanted to bring my staff to support me in my job - and this possibility was not very clear.
"Everything was going well but we stopped at a crucial point for both of us.
"They needed to announce the new England coach in a period that was impossible for me. I have a contract until 31st July with Portugal.
"We created a very good relationship but the problem was, the person I am, I couldn't decide to be a coach of another country before a World Cup when I was representing Portugal.
"Imagine if I meet England during the World Cup and I have to say to my players, 'Die for Portugal'. I only can say to my players what I really feel.
"Perhaps in Europe it's normal but I am Brazilian and I didn't feel good in that situation.
"Being coach of England is a dream for every coach in the world and I was very happy when the talks happened.
"I liked the people I met from the FA very much. I hope people understand the situation and one day, why not, I can coach the English team, when I am free."
