Reigning champions Clive Wheeler and Ken Bartram will be bidding to win their second successive Castrol Polo Challenge title this weekend.

The West Sussex duo and their Group N Polo will start today's Trackrod National Rally in Yorkshire holding a 17-point series lead and with everything to play for on the championship's penultimate round.

Class victory on the Trackrod would settle the title in favour of Albourne-based Wheeler, irrespective of where his title rivals Jari Laakso and Kenny Brown were to finish.

That is if, as expected, Wheeler plays his 'Joker' card in Yorkshire, which would add 50 per cent to any points he scored.

Wheeler and Bartram, from Hurstpierpoint, will be hoping to do just as they did on the Trackrod in 2002 - win in style and settle the championship with a round in hand.

As last year, their prize would be a brand new Volkswagen Polo road car.

If they do not win in Yorkshire, second or third in class on the Trackrod would do for Wheeler, so long as it is not Laakso who takes the win.

Both Finland's Laakso and Lancashire-based Brown played their 'jokers' on the last Castrol Polo Challenge round, the Manx.

Laakso squandered his with a non-finish but Brown came up trumps with a maximum score.

However, his title hopes are the faintest of the three and his best chance rests on Wheeler and Laakso failing to score in Yorkshire.

Wheeler took class honours on the two opening rounds of the championship, the Pirelli Northumbria Rally and the Red Dragon Rally.

The Trackrod National Rally features nine special stages and 63 miles of competitive driving in the Yorkshire forests. The event starts and finishes in Malton.