England decided at half-time to play the remainder of the game as braces from Ross Barkley and Raheem Sterling and goals for Marcus Rashford and Harry Kane ensured a thumping win for the visitors.

While some questioned the decision of the visitors to play out the remainder of the qualifier, Henderson insisted the players had good reason to.

"It was disgusting," the Liverpool midfielder said.

"It shouldn't be happening and something needs to be done about it but I thought the lads were outstanding and if I was angry I'm sure they were angry as well.

"I thought we let the football do the talking and we made them suffer, that is what we wanted to do.

"I obviously wasn't happy with the situation that we were in, it wasn't nice to be involved in and it shouldn't be happening in 2019, it is very disappointing.

"But, at the same time, I felt as though as a team we dealt with it so well, we touched on it before we came here just in case it did happen and unfortunately it did.

"So we spoke together and the decision was that we carried on because if you leave the pitch and stop the game they win, really.

"That is how we looked at it, it is what the message was in the dressing room at half-time and we wanted to go out in the second half and make them suffer and make their team suffer on the pitch and I think we did that."

Henderson admits he was also left bewildered by the reaction to the stadium announcement calling on any racist behaviour to stop at the risk of the game being abandoned, but was full of praise for the away supporters inside the Vasil Levski National Stadium.

"I thought our fans were brilliant," he added.

"All night I thought they were outstanding, I just hope there was no trouble after the game and everyone got home safely and everything was OK.

"But our fans stood behind us like they always do. They are unbelievable all the time, but it is times like that you want them right behind you and they certainly were and that just brings us together even more.

"It was another plus for us in terms of that, it is obviously a tough one, we are obviously happy with the performance, but still feel like it shouldn't be happening in this day and age.

"To hear the announcement about the racism and then the whole stadium whistling was a bit strange, I'm sure something will be done."

UEFA on Tuesday charged the Bulgarian Football Union with the racist behaviour, throwing of objects and disruption of a national anthem by their fans.

The governing body's president Aleksander Ceferin has urged the "football family" to "wage war on the racists", while FIFA president Gianni Infantino called for "life bans from stadiums for those who are found guilty of racist behaviour at a football match".

FIFA said it would extend any sanctions imposed by UEFA worldwide.

The English Football Association has also been charged with disruption of a national anthem, as well as providing an insufficient number of travelling stewards.