IF you ask football fans to name the biggest game in English football, it's a fair bet that most of them will come up with the FA Cup final.

Some Middlesbrough supporters will no doubt sing the praises of the Carling Cup decider, while followers of Manchester United and Arsenal could justifiably point to games between the two sides as highlights of the football calendar.

All of those matches have a major emotional impact but, when it comes down to bare economics, one fixture stands head and shoulders above the rest.

When West Ham take on Crystal Palace in this afternoon's First Division play-off final, the two London sides will be fighting for the biggest first-prize purse in the English game.

The winners will win promotion to the Premiership and the estimated £25m windfall that brings - the losers will go home with nothing.

There is no other game in which so much will be decided by so little.

After 48 games of slogging from one end of the country to the other, the fate of two football clubs will be decided by one game, possibly one kick.

Just ask Michael Gray. The former Sunderland full-back knows all about fine margins after his missed penalty settled the 1998 play-off decider and subjected the Black Cats to 12 more months in the First Division.

Gray's spot-kick nightmare came at the end of the greatest play-off final of them all - a helter-skelter affair that saw Sunderland concede the lead three times as Charlton battled back to earn a 4-4 draw.

The Black Cats would have been in this afternoon's final themselves were it not for more shoot-out despair against Crystal Palace but, in their absence, the Eagles and West Ham will be charged with maintaining the play-offs' hard-earned reputation for excitement.

There is every reason to expect the two clubs to deliver as some of London's most loyal fans decamp at Cardiff's Millennium Stadium.

Both clubs have a proud Premiership pedigree, but there is no doubt which of them needs a win this afternoon most.

West Ham have seen their squad ripped apart since they were relegated from the top-flight last season, but they are still saddled with a £33m debt and a wage bill higher than almost any other in the First Division.

Another season outside the Premiership would place a considerable strain on the club's finances.

Alan Pardew certainly appreciates how much is at stake, admitting that the financial implications of this afternoon's game are "daunting".

But the Hammers boss has reason to be optimistic at the end of a season that has seen his side recover from a slow start to finish fourth before edging out Ipswich at the play-off semi-final stage.

An attack that includes Bobby Zamora, Marlon Harewood and David Connolly is equipped to survive at the highest level, but West Ham remain vulnerable at the back.

Pardew remains a Palace hero after scoring the goal that took the Eagles to the FA Cup final in 1990 and, ironically, his opposite number, Iain Dowie, is equally revered at Upton Park thanks to 96 whole-hearted performances for West Ham.

Perhaps the only place he is more popular is Selhurst Park, after turning Palace's season on its head since moving to London from Oldham in late December.

Dowie has overseen an incredible run of 14 wins from 20 games and, while Palace's most recent outing was actually a 2-1 defeat to Sunderland, the way they held out with just ten men spoke volumes for their tenacity and team spirit.

The loss of the suspended Julian Gray will be a major blow though, and the Eagles still look to be over-reliant on the goalscoring capabilities of hot-shot frontman Andy Johnson.

Bristol City meet Brighton in the Second Division showdown tomorrow.

Both sides were made to sweat before booking their place in the final, with Bristol City needing two goals in the last three minutes to beat Hartlepool and Brighton leaving it just as late before Adam Virgo's 120th-minute strike set up a penalty shoot-out win over Swindon.

Danny Wilson's City side go into the game as favourites, thanks to an impressive nine months that saw them miss out on automatic promotion by a solitary point on the final day of the campaign.

Brighton have made it to Cardiff despite the off-field turmoil caused by their proposed move to a new ground but, despite 26-goal striker Leon Knight declaring himself fit following a leg injury, Mark McGhee's side will need to be at their very best to cause an upset.

Monday's Third Division final pits Huddersfield against Mansfield and, after holding an automatic promotion spot until the final 15 minutes of the season, the Terriers will be desperate to start their climb back up the Football League.

Huddersfield would probably have been promoted already had they not had to sell Jon Stead to Blackburn halfway through the season, and they should have too much for Mansfield.