TV's rating war a knockdown fight Seven's House Rules contestants. THE NAIL guns will fire tonight in the $20 million TV home renovation battle as Channel 7 and Channel 9 declare war. Nine launches its assault with the latest series of The Block Sky High at 6.30pm while Seven's House Rules debuts on Tuesday night with the station having high hopes of demolishing its rival. So confident is Seven of denting its opponent, it has programmed House Rules against The Block Sky High three nights a week. The DIY reality series are indicative of the broader ratings battle the two networks are engaged in now that Ten is no longer a competitor. "It's Seven and Nine hating each other," Audience Development Australia chief executive David Castran says. What's driving it is that Ten has dropped out of the race, more or less. They are down to a lower share - around 15 per cent. Seven and Nine are in a real war, one of the worst I have ever seen. This is all about who will benefit from a weak Ten, who is eating off the carcass. With each network desperate for greater audience share, they're resorting to dirty tricks to stop viewers switching channels. TV bosses admit to running programs late, changing shows at the last minute and pitching similar shows against each other. In recent weeks Nine pulled an episode of The Voice on the day of broadcast, with insiders suggesting it was being saved to air against House Rules. It also ditched Celebrity Apprentice from its premiere slot after TV guides had already gone to print. And Seven ran the grand final of My Kitchen Rules 14 minutes late to keep viewers locked to the network for the premiere of its new drama, A Place To Call Home. On the same night The Voice ran late to prevent viewers switching over for the My Kitchen Rules winner announcement. Castran says there is only one loser: the viewer. I don't think viewers are a commodity anymore. But they have a much larger range of things to do with their time now and they are not as desperate as they were 10 years ago so networks need to be nice to them. David Knox, editor of website TV Tonight, agrees. "Late starts, fake TV listings, withholding schedules from media, dumping of episodes - Nine and Seven are playing games with the poor viewer stuck in the middle," he says. What networks are increasingly lacking is a confidence in their product and viewers can smell it a mile off. Nine's director of programming Andrew Backwell says multi-channels and an increasingly competitive market means networks have to do all they can to snare audience share. "We are running a business, trying to get the biggest share of advertising revenue," Backwell says. I would rather overlap a show to keep an audience on Nine. It is a delicate balance (and) we don't always get it right and we often upset the viewers but we do respect our viewers. Seven says live and event television often runs over the allocated time, and insists House Rules isn't a rip-off of The Block. We are renovating an entire house each week which hasn't been seen before. Allen says it comes down to the advertising dollar and Seven want a slice of the renovation pie. We have had advertisers in The Block in the past (and) it has looked awkward. But when it is natural and the product is the hero because of it, advertisers would walk on broken glass to get that," he says. A lot of these advertisers haven't been big TV advertisers before, they haven't had an outlet. For companies like Bunnings and Mitre 10 this is fantastic. It is gold ... the market is literally falling over itself. Allen says this is the first wave of program poker viewers can expect. A fortnight from now we will be talking about MasterChef and Offspring and whatever Ten's format is. Then they will be up against each other.