England were subjected to a nerve-shredding wait to discover their T20 World Cup fate, relying on a helping hand from Ashes rivals Australia to reach the next stage of the tournament.

Jos Buttler's side did everything they could to book their spot in the Super 8s, defeating Namibia by 41 runs in a rain-shortened game in Antigua, but retired to their beachside resort for the night knowing their destiny was no longer in their own hands.

A shock Scotland victory in the Group B decider against Australia would have seen them edge their fellow Britons for second place and, for long periods, they threatened to become the first associate nation to defeat Australia since 1983.

But Australia finished strong thanks some destructive hitting from Travis Head and Marcus Stoinis, squeezing out a narrow win with just two deliveries remaining. England were surely watching along on television as the game reached its dramatic conclusion just a few minutes before midnight and would have found themselves in the unusual position of roaring on their bitterest foes.

Much ink had been spilled when Australian seamer Josh Hazlewood suggested last week that his side may be open to engineering England's exit from the competition but, despite an unusually sloppy fielding display containing six dropped catches, a bold chase of 181 proved there was no skullduggery at play.

England, having come perilously close to an early flight home, will now be moving to St Lucia where they will begin their Super 8 campaign against co-hosts the West Indies on Thursday. Games against South Africa and surprise qualifiers the United States follow as they chase a semi-final place.

It had earlier looked as though rain could ruin England's hopes. They were delayed for three hours against Namibia as heavy downpours battered the Sir Vivian Richards Stadium, but conditions cleared enough to allow a 10-over match to take place.

A nervy start with the bat was put to bed as they posted 122 for five, Harry Brook nailing 47 not out from just 20 balls and Jonny Bairstow making 31. Their bowlers then had far too much for opponents who only scrambled to 84 for three after the unusual sight of Nikolaas Davin voluntarily retiring to allow the more powerful David Wiese to take his place.

"It's a big relief, a stressful day, but we put in a good performance," said Buttler at the close, unaware of just how tight things would get in the coming hours.

"We've done all we can do."

Bairstow took a pragmatic approach to the prospect of seeing his side's tournament destiny being settled elsewhere, insisting England were happy with their own efforts after bouncing back from their own heavy defeat against Australia with a pair of convincing wins.

"I'm sure we'll be keeping an eye on (Australia and Scotland) for sure but at the same time there's not much we can do about what happens over there," he said.

"We've done everything that's in our hands to do. There was a lot of chat about the net run-rate but we've overcome that and we've overcome the other challenges that have been put in front of us. As a group, we've stuck together really tightly.

"That Australia game was a tough game and they outplayed us in that, fair play to them. But the way that we've responded as a group, how tight we've stayed over the last week or so, we've accepted the challenge that's been put in front of us and we've responded very well to that."