Every so often, a hand reaches out from the camera to assist.

Yeah, we had a lot of free time, explains Horne.

We also used to film each other playing squash in suits for some reason.

No-one really watched them, but it filled the time.

I guess theres something in it, says Horne.

Just thinking of really pointless things to do and seeing how well we could do them.

Youre probably on to something there.

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For the uninitiated,Taskmasteris pure TV joy.

Greg Davies judges the winner of each round and hilarity genuinely ensues.

Gregs treatment of them is very British.

The actual tasks, its almost like that Japanese gameshowTakeshis Castle.

I dont know if itll catch on anywhere else.

In the UK version, the five contestants are more cosseted.

Every series we have to tell people that theyre not allowed to climb on the roof, he says.

Theyre always trying to climb on the roof and theyre not allowed to because of insurance which is frustrating.

We have to get crash mats even if somebodys jumping from one metre.

Aimless tasks have been a mainstay of Hornes TV career so far.

Before that, Horne worked behind the scenes in the early years ofBig Brother.

I definitely got some inspiration from it.

What has filming five series ofTaskmastertaught Horne about the human condition?

I like that we can pretend its all very deep!

I also think the cleverest people can do the stupidest things and vice versa.

Thats certainly borne out on the show.

Its that kind of show.

Im amazed at how little the current contestants pay attention to anything thats gone on previously.

How much did Al Murray spend in total during his series?

I think its reasonable, you might win.

The star prize from series two onwards has been is a statue of Greg Davies head.

The winners do treasure it.

I like imagining that its on top of their telly, says Horne.

Five mini-prizes provided by the comedians along a given theme each week are also up for grabs.

And yes, says Horne, they really take those home with them.

Other souvenirs have ended up in the houses of various participants over the years.

Tim Key framed the painting he did of a horse while riding a horse, as did Frank Skinner.

For some reason, says Horne, Ive got Roisins [Conaty] horse picture at home.

What makes a great task?

I like it when people read between the lines.

Paint the biggest thing red was a past suggestion of Hornes that was nixed by the shows producers.

That sounds brilliant, I suggest.

What was the problem there?

I agree with you, says Horne.

I think thats a good one.

Its not our house unfortunately, we rent it.

The key to it all, says Horne, is that the reactions in the studio are completely genuine.

Thats the most important thing, he says.

Theyve never seen anything that theyve done before or that anyone else has done.

That reaction is crucial.

Quite often, theyre laughing more than the audience.

Thats a thing we really hold precious.

Its aweirdday, but really fun.

Which other task ideas never made it in front of the cameras?

Then a few series later we thought, thats a great task!

There have been lessons learned over the years.

To keep the home-made spirit of the show, the team now tries to avoid tasks involving specialist equipment.

The tasks are only half the story.

A truly great series ofTaskmasterrelies on the right combination of comedian contestants.

When casting, theyre not specifically looking for particular character traits, says Horne.

Does that give him an edge?

No, says Horne decidedly.

It doesnt make things easier for him.

If he was looking for leniency, he didnt get it.

(Of course its going to happen.)

With four years under their belt, its much easier to persuade people to take part, he says.

Theyve seen it now, which helps.

A champion of champions special is also on the cards.

Its pretty likely, says Horne.

I cant reveal anything but were hoping.

Finally then, what can we expect from series five?

One word, says Horne, Coconuts.

Taskmaster series 5 starts tonight at 9pm on Dave.