Captain Steven Gerrard, who said England "stopped playing" after halftime, pleaded with the team to shake off their alarming habit of sitting on a 1-0 lead.
"There was a lot of experience out there and we showed that in the first half -- we controlled the game. But the problem is, at 1-0 you're always vulnerable," the midfielder told the FA's website.
"You've got to go on and get that second goal to be in complete control and we didn't do that."
However Hart, despite his blunt assessment of England's lopsided performance, said Montenegro had not posed too much of a threat and had been lucky to score through Dejan Damjanovic with 15 minutes remaining.
"It was a scrappy goal. I'd imagine they'll say it was coming but I think that was the only way they were going to score, with the ball bobbling around and someone being in the right place at the right time."
Goalkeeper Joe Hart was called into action on numerous occasions in the second 45 minutes as England, utterly dominant in the first half where they scored early on through Wayne Rooney, buckled under pressure following the break.
"First half, thoroughly in control; second half, we made it hard for ourselves and we had to dig deep," a less than impressed Hart told Sky Sports News.
England are becoming experts at letting leads slip against 'lesser' opposition, evidenced by their 1-1 draws against Montenegro and Poland in their qualifying group.
The situation is not yet bleak for England who will still be favourites to qualify as group winners come October given they host both group leaders Montenegro and third-placed Poland, who are four points behind with a game in hand.
"It is in our hands because we play Montenegro and Poland at home and we have to go to Ukraine," said manager Roy Hodgson.
Montenegro, top of the table by two points, can go five clear when they host fourth-placed Ukraine in June. England's next fixture is at home to Moldova in September.