Australia needs to win the Ashes to retain No 1 ranking

England will have to make history to leapfrog Ricky Ponting's side

Australia's lead over number-two ranked South Africa to be trimmed to two ratings points when annual update is carried out on 1 August

Australia and England go head to head in the mouth-watering Ashes series in Cardiff on Wednesday with Ricky Ponting's side needing to win the series to retain its number-one ranking in the Reliance Mobile ICC Test Championship table.

Although a drawn series will be enough for Australia to retain the Ashes, thanks to its 5-0 victory in the last series in its backyard in 2006-07, this outcome would drop it to second place for the first time since the current rankings system was introduced in 2003.

Today's championship table may reflect a nine-point lead for Australia over South Africa but that lead will narrow to just two ratings points when the annual update is carried out on 1 August and all series completed before August 2006 fall off the table.

These results include Australia's back to back 2-0 and 3-0 wins over South Africa in 2005-06, hence reducing the gap significantly.

As such, when the annual update is carried out on 1 August Australia will drop four points to 124 ratings points while South Africa will gain three ratings points to rise to 122 ratings points. England, which currently sits on 101 ratings points, will slip to 99 ratings points.

England could overtake Australia at the end of this series. But to make that happen, it will have a create history and win every Test, something which no English side has done in a series of five or more Tests since the start of the Ashes over a century ago.

Below follows a table of all Ashes series scenarios:

In the Reliance Mobile ICC Player Rankings for Test batsmen, Australia has four batsmen in the top 20 with captain Ponting leading the way in sixth place. Vice-captain Michael Clarke (eighth), Mike Hussey (16th) and Simon Katich (17th) are the other Australia batsmen inside the top 20 and eyeing an upward movement.

In ninth position, Kevin Pietersen is England's highest-ranked batsman while captain Andrew Strauss sits in 18th spot. Just outside the top 20, England has Alastair Cook and Paul Collingwood in 21st and 23rd positions respectively while Ian Bell is in 33rd spot.

The batting table is headed by Pakistan captain Younus Khan while Sri Lanka captain Kumar Sangakkara is second and Gautam Gambhir of India is third.

In the Reliance Mobile ICC Player Rankings for Test bowlers, Australia fast bowler Mitchell Johnson has number-one ranked Muttiah Muralidaran of Sri Lanka and second-placed Dale Steyn of South Africa firmly within his sights while Stuart Clark in fourth position also has a good chance of closing the gap with the top three bowlers.

England's bowling looks to have more depth as it has three bowlers inside the top 20 while two are just outside the top 20. James Anderson is England's high-ranked bowler in eighth place while Ryan Sidebottom is 12th and Andrew Flintoff is 18th.

Eyeing a return to the top 20 are left-arm spinner Monty Panesar (21st) and Graeme Swann (23rd) while Stuart Broad is in 37th spot.

South Africa's Jacques Kallis leads the Reliance Mobile ICC Player Rankings for Test all-rounders with Johnson second and Flintoff fifth.