Alastair Cook must wait for confirmation that he will lead England into their World Cup winter - but he is in no doubt about their potential for "scary" improvement en route.

Cook signed off an eventful and decidedly mixed first summer of his and coach Peter Moores' new era with a badly-needed win, on the back of Joe Root's career-best 113 at Headingley, to dodge a Royal London Series whitewash against India.

England defended 294 for seven, despite half-centuries from Ravindra Jadeja (87) and Ambati Rayudu (53), to prevail by 41 runs.

Cook was assailed for the umpteenth time in a post-match press conference this summer on his determination to remain as captain, and any guarantees he has received that he will be doing so.

As ever, he was able to assure his questioners on the first point but not the second.

He is unequivocal, though, on England's likely rate of progress as they devote themselves exclusively to 50-over cricket until the end of the World Cup in Australia and New Zealand in March.

Their journey will begin with seven one-day internationals in Sri Lanka in November, a tour for which England will name their squad and captain later this month.

"The big improvement I think we can make is quite scary," said Cook.

"That's what we've got to get our heads round now as players - to go and put the real hard yards in November at home, then when we get to Sri Lanka, work our nuts off to improve.

"Obviously, it will be spin-orientated there...so we've got six weeks of being able to really improve our skills, being able to knock the ball about when we want to, take the big shot on when we need to.

"The shot I played (here), for example, I didn't execute. It was the right shot, I just messed it up...if I can get better at playing shots like that, it will help us as a side."

He is not getting carried away, in the meantime, with England's consolation success in Leeds.

"It's nice to win, but we've lost another series," he added.

"We've got a great opportunity as a side now, for six months to work on our one-day game.

"I've never experienced it in my one-day career, and I know people like Jimmy (Anderson) haven't.

"I'm looking forward to Jimmy working for six months on his slower balls and yorkers - because he can do pretty much everything else with the ball."

There are vexed questions for England to answer, however, after a series dominated by India and in which the hosts were unable to settle on a trusted team selection.

"The idea will be to have a batter in the top six who bowls," added the captain.

"That balances your side a lot better.

"We had a lot of options (here) with the ball, which is nice as a captain - but the only way of doing that is playing a batter (who bowls) in the top six.

"Unfortunately, this series has probably shown up a few more questions than answers - and we're going to have to go away and think about it quite hard."