England's one-day rise surprises Cook

Alastair Cook admitted his surprise that he is in charge of an England side who find themselves officially top of the ICC one-day rankings. The surprise might be shortlived. If South Africa beat England in the first of five ODIs in Cardiff on Saturday, they will overhaul them.

At least England's reign as the No. 1 Test side lasted a year; their achievement in the one-day game might only last a day. When the usual crop of dignitaries present them with the Reliance ODI Shield, Cook would be well advised to accept the award with the most modest expression he can muster.

"I don't think we feel like No. 1," he said. "It was something we were aiming for a bit later on. We've got such a long way to go."

If South Africa, who trail England by one-sixth of a rating point, win in Cardiff they will become the first country to hold the No. 1 rankings spot in all formats of the game, having deposed England as the top-ranked Test team at Lord's on Monday. To retain that position, they would have to win the series by at least 3-2.

For England's one-day side to be seeking to improve on poor displays in the Test format is an uncommon feeling. Until this year, the assumption had been that England's Test side was the stronger, winning back-to-back Ashes series while the 50-overs side was a poor relation, looking as far as ever from winning a major one-day tournament for the first time. Perceptions are changing. This series will go a long way towards showing whether the shift is more than a temporary aberration.

Two replacement captains help to bring some significance to the series. AB de Villiers assumes command of South Africa, leaving Graeme Smith to spend time, between batting, with his wife and a new baby girl, Cadence, whose birth he returned to see in between the first and the second Tests. Smith spent so long grimacing and growling at England's attack in the Test series that if he briefly forgets himself the new arrival in the Smith family could get a bit of a shock.

New captains and fresh faces have their advantages. The threat to continuity caused by a change of personnel can be offset by a renewed sense of zest. A change is as good as a rest and, in international cricket, change is the best option there is because there is little chance for rest. "This is why three captains seems to work quite well," Cook said. "Certainly I'm ready to go again with the challenge of leadership. When Broady steps in for the Twenty20s, he'll really want to drive the team on."

In normal circumstances, it would be Stuart Broad's Twenty20 leadership that would be observed most closely over the coming weeks. The World Twenty20 is less than a month away and three t20 matches against South Africa therefore hold more importance than usual for both sides, even allowing for the very different conditions that will face them in Sri Lanka.

But these are not normal circumstances. Cook is regarded as heir apparent to Andrew Strauss as Test captain, although Michael Atherton, the former England captain, deservedly praised the leadership qualities of Matt Prior in The Times on Thursday, not just because of his fighting on-field qualities but because he was the one person brave enough to ring up Kevin Pietersen - without permission as it happened - and try to bring some sense to a stand-off that has demeaned all who are involved in it.

"After 18 months I feel more comfortable in the role, happier making decisions in the field and in selections with Andy Flower," Cook said.

He has eased himself into captaincy gradually, not as much groomed for the job as receiving a manicure, full facial and Ayurvedic massage; pretty much everything, in fact, apart from colonic irrigation. Naturally, he was asked about Pietersen's part in England's future and twice claimed the matter was "above my head." It did not smack of leadership, but it a dangerous topic to show leadership on.

There is no doubt that Smith runs South African cricket; de Villiers is a well-mannered understudy who knows the extent of his power and who has Smith in the background for advice should he need him. There is still not much doubt that Strauss runs England cricket. But despite the emphatic support he has received from his coach Andy Flower, who does not regard the matter as up for discussion, it is a dangerous time in a captain's career when he reaches an age where he is most often praised for presentational skills rather than the runs he gets or the fields he sets.

Depict Strauss as a successful England captain and he needs to be depicted as an influential performer in whites, not prized as a man offering calming and intelligent off-the-field guidance, however invaluable that might be. There again, ECB officials are open to so little public scrutiny these days that somebody has to be the public face of English cricket.

Ravi Bopara returns for England after a tough personal time and the presence of Cook, an Essex team-mate, as captain, will help him settle back into the job. That his mind will be attuned to the task should not be assumed to be automatic. A planned return for England Lions against Australia A was aborted, a run-out for Essex against Netherlands in the CB40 brought a score of 1 and his guest appearance for Gloucestershire brought three wickets but little reward with the bat.

South Africa have a different feel to the side that capitulated in the one-day series in England in 2008. Instead of familiar faces from the Test campaign, they have more new faces, some of whom have got into trim in a short tour of Ireland.

De Villiers suggested that England might be a specialist batsman light. "It's something we'll be attacking," he said. "They may be conservative up front because they are a batter light, they don't have the wicket keeper at No.7 like most teams. But I can't see them carrying a lot of scars from the Test series, maybe just a tiny little mental factor, but if we don't start well that would soon be lost."