It would have seemed scarcely believable only a couple of weeks ago but England go into the fourth ODI in Dubai on Tuesday with an excellent chance of securing a 4-0 whitewash over Pakistan.

It would complete a remarkable turnaround from a side that, coming into the series, were all but written off by most observers. After all, England's failure to adapt to conditions in the UAE had just condemned them to a 3-0 Test series loss and they had a poor record in ODIs outside the UK and in Asia in particular. Their subsequent success has been quite unexpected.

It has not been undeserved, though. While Pakistan, back to their mercurial best and worst, have offered surprising little resistance, the nucleus of an England side is emerging that offers some hope that, after many years of disappointments, they may have some hope of sustaining a realistic challenge in the next World Cup.

They are still a work in progress. While it may prove devilishly tough for anyone outside the current squad to force themselves into the bowling attack, there are still a couple of batting positions that could become vacant. The England management remain keen to see Jos Buttler in ODI action, while Ben Stokes, the Durham allrounder who has missed the tour due to a finger injury, is another of whom much is expected.

The formula is beginning to come together, however. Alastair Cook's emergence as a quality ODI opener is now disputed by few, while Kevin Pietersen's return to form provided a reminder of what a dangerous player he can be for England.

Amid all the encouraging signs, it would have been easy to overlook Eoin Morgan's elevation to No. 3 in the batting order in the third ODI in Dubai. It is a position that has been occupied for some time and with some success by Jonathan Trott, but Morgan's promotion signifies a rethink. England now intend to utilise Morgan as their ODI No. 3 if Cook is the first man out in order to retain a left-hand, right-hand combination of batsmen at the crease. Where that leaves Trott is open to debate. He has endured a quiet tour by his standards but an ODI average of 49.21 and a strike-rate of 78.18 cannot be lightly dismissed.

Despite the number of runs, there are those who have continued to question Trott's presence in the side. They claim, despite quite a lot of statistical support to the contrary, that he is one-paced as a batsman and that he will not help England to the large totals in excess of 300 that, it is anticipated, will be necessary to win the 2015 World Cup. Somewhat incongruously, England's most successful 50-over player of the last couple of years is often blamed for England's failings as an ODI side.

The problem for Trott is, if he does not bat in the top three, where does he bat? He is not the most obvious choice to come in with only a few overs remaining and, with the likes of Ravi Bopara, Morgan and Samit Patel offering slightly different options to the team, Trott's position is coming under scrutiny. If England are keen to utilise the final ODI of the series against Pakistan to have a look at Buttler, it is possible he could displace Trott. Tim Bresnan could also come in from James Anderson.

"I've had my pads on to bat at three for the first three ODIs because we like the right-hand/left-hand combination, especially when there are two spinners on," Morgan said. "It's been the same throughout the series. It's just been that Cook has been in unbelievable form and I haven't got a bat. The fact we've got off to good starts has helped. I come in and move it on. My strengths come into play and that's where we use it."

Morgan has experienced a poor tour to date. He averaged just 13.66 in the Test series and was particularly troubled by the spin bowling of Saeed Ajmal and Abdur Rehman. Since then, and partly due to Cook's excellence, he has enjoyed little opportunity in the three ODIs. He admits it has left his place in the Test side in doubt.

"I haven't felt out of form here, I just haven't got the runs I wanted. I know where I want to score"
Eoin Morgan

"It's been hard work," he said. "The Test series was very tricky. The skills levels on our behalf - and mine as well - weren't up to scratch. We struggled.

"I haven't felt out of form. I've been out of form before and there are times I've not seen where my next run is coming. Here I just haven't got the runs I wanted. I know where I want to score. I think the fashion in which I've played - running down and hitting over the top, hitting from the crease - show I'm still in reasonable touch as opposed to not knowing where my next run would come from.

"Ajmal has been in a fantastic run of form of late and again, having not played in four or five months caught up with us - me in particular. I've been off for quite a well. Even though I spent some time in India before Christmas it doesn't replicate what you're up against. It was hard work.

"I don't worry about my Test place. I always put myself under a lot of pressure, particularly in the longer format of the game. But I haven't scored enough runs to justify being number one in the side. The pressure I put myself under is enough."

Morgan took comfort in England's improved ODI form, but provided a timely reminder that the side have a long way to go before they can be considered realistic World Cup contenders.

"In our last summer we've come a long way," Morgan said, referring to the series wins over India and Sri Lanka achieved in England in 2011. "But the stint we did in India - when I wasn't there - pegged us back a long way. So we were starting from scratch in terms of playing in this part of the world.

"We've got off to a fantastic start. But it comes back to a case of not getting carried away with where we are or where we want to be. Where we are is number six [now No. 5 after winning the first three ODIs against Pakistan] in the world; where we want to be is number one in the world by the World Cup in 2015."

Edited by Alan Gardner

George Dobell is a senior correspondent at ESPNcricinfo