It is chucking it down at Wembley as the players and officials head out. Those expensive-looking suits that Steve McClaren and Harry Redknapp are wearing drenched already. No sign of an umbrella though.

Steve McClaren shakes hands and shares a joke with counterpart Harry Redknapp as the two teams wait in the tunnel to head out. No such shenanigans between the players, with absolute focus etched on each of their faces. Serious stuff now.

Image source, Getty Images

Where would QPR be without the goals of Charlie Austin this season? Of the 25 players Harry Redknapp has signed during his time at Loftus Road, former bricklayer Austin has arguably been his most important.

Signed from Burnley last August, Austin banged in 20 goals over the course of the season, even more impressive considering he had a lengthy spell out with injury. It was no coincidence that QPR's form dipped while he was absent, and improved considerably on his return.

He seems a good egg too. Having donated two tickets for today's game to a fan who has jetted over from the United States.

BBC Radio 5 live

The 27 players to have represented QPR in the Championship this season have a staggering 4,264 Premier League appearances between them. That's some experience but manager Harry Redknapp resents the popular notion that his side should have been promoted automatically.

He tells BBC Radio 5 live: "I don't know why people say we should have gone up automatically, we lost 18 players in the summer and some of them were very good players. The likes of Loic Remy - what would he cost now? We had to throw a new team together. I think people talk nonsense when they say we should have gone up automatically."

Image source, Getty Images

Prior to this season, Derby striker Chris Martin had a goalscoring record Shola Ameobi would have scoffed at. This campaign, however, he has been an absolute revelation for the Rams and arguably their most important player.

He bagged 25 goals this season, including seven in the Rams' final eight games on the way to the play-off final.

There is arguably no other player in as good form as Martin going into this game.

Paul Fletcher
BBC Sport at Wembley

"A remarkable drop in temperature at Wembley, very dark skies up above. Brace yourself. Still, with Steve McClaren choosing to watch his team from the stands these days he shouldn't get too wet. Harry Redknapp, on the other hand, could be in for a repeat of his second-leg soaking. Ruined suit and all."

The atmosphere is electric at Wembley with just over 15 minutes until kick-off. In a couple of hours, one half of Wembley will be bouncing in ecstasy, the other half inconsolable. Having experienced both emotions at a play-off final, I know the nerves now must be almost excruciating.

It may be the richest game in world football but for QPR, it could prove the most costly if they do win.

Any Football League club that exceeds an £8m loss for the 2013-14 campaign when their accounts are submitted by 1 December this year is subject to a punishment.

QPR's wage bill for 2012-13 was £68m, so the prospect of them posting losses way above the permitted £8m is not out of the realms of possibility. If they stay down, the punishment would be a transfer embargo, go up and they could be liable to pay Fair Play Tax in January - a fine reportedly as high, external as £58m.

David:, external I hope Derby win, it would be a victory for a humble attacking side versus a side with big money, attempting to 'buy' promotion back.

Jamie:, external How on earth did that QPR team not get promoted automatically?!

Glenn:, external Derby to win and get promoted today. Steve McClaren to inspire the rams with his Dutch/Derbyshire accent!

Image source, Twitter

Steve:, external My view at Wembley. I am going for a 3-2 Derby win. Jake Buxton in the 91st minute!

At 36%, the teams that finish third in the Championship have the highest percentage of securing promotion via the play-offs.

That is good news for Derby, who finished third, but the bad news for QPR is that the team finishing in fourth has gone on to win the play-offs in only four out of the last 25 finals (16%), the least of any position.

The last time a team finishing fourth won the play-offs was way back in 1998. QPR to buck the trend?

Image source, Football League

A Geoff Hurst moment looks unlikely at Wembley today as the game's match officials tested the Goal Decision System ahead of kick-off. Could an entire season of work for Derby or Queens Park Rangers come down to the width of a ball?

The thought alone is brutal.

I wonder if Harry Redknapp will be regretting giving Steve McClaren a job last July? Redknapp brought the former Middlesbrough boss to QPR as a coach, a position he held until Derby came calling in September.

Plenty of time for him to get to know the strengths and weaknesses of the QPR players, could that work in his favour today?

Image source, @NiallHoran

Derby County have some celebrity support in the shape of One Direction singer Niall Horan,, external who will miss the play-off final as he is playing at Radio One's Big Weekend in Glasgow.

He tweeted this picture of the last time his side were in the play-off final in 2007, along with a good luck message: "HUGE good luck to Derby County today in the play-off final! Gutted I can't be there ! My father is going though!"

Paul Fletcher
BBC Sport at Wembley

Image source, Getty Images

"It is a huge afternoon for Will Hughes, who is currently going through his warm-up routine with the rest of the Derby side. The 19-year-old, who was educated at Repton and has been linked in the past with Barcelona, scored in the second leg against Brighton and keeps his place in midfield. He is a talented ball player with great vision and passing range but starting him ahead of Craig Bryson is a big call by Steve McClaren."

Derby players are going through a few drills on the edge of the immaculate Wembley turf at the moment, the distinctive, almost white shock of hair flashing by as midfielder Will Hughes does a few sprints. He has been a key player for Derby a couple of seasons now. Hard to believe considering he is just 19.

Derby have plenty of experience of the play-offs at this level. They won promotion to the Premier League via this route in 2007, and were semi-finalists in 1992 and 2005.

QPR, meanwhile, have never featured in the play-offs at this level but they have a manager who certainly has proven pedigree of winning at Wembley. He won the FA Cup there with Portsmouth in 2008.

Phil Brown
BBC 5 live pundit at Wembley

"Before the game there are nerves. You just want to do your team talk and get on with it. If it's 1-0, my word there are nerves. Yes you feel them. I think this will be close and regardless of the experience these managers have, they will be feeling the pinch by the end."

There might be a few nervous fans, players and managers at Wembley today but the BBC Radio 5 live team are all in good spirits. Mark Chapman, here, gleefully snapping a photo of Phil Brown and Robbie Savage.

Listen to their thoughts on BBC Radio 5 live.

Ryan, Edinburgh: Living in Scotland I'll be supporting Derby today with so many former SPFL players there. Connor Sammon, Jonny Russell, Craig Forsyth, Craig Bryson, Lee Naylor and I suppose you could count John Eustace in there too, along with Paul Coutts who was a Scotland U21. Our game takes a beating from fans south of the border so it would be nice to see some of the players that played up here succeed and get Derby to the Premier League.

Chris: Hope Nigel Clough was invited to the game today. We are where we are due to the foundations laid by him and he deserves some recognition.