As mentioned, with Martin Freeman trekking across Middle Earth this Christmas, David Tennant has stepped up to the role of put-upon teacher Donald Peterson, who signs on to teach Mr Poppy’s (Marc Wootton) class at St Bernadette’s. With a year’s worth of teachers coming and going, Mr Poppy and the class are a team of underdeveloped troublemakers, dedicated to making life incredibly difficult for the new man in charge. Keen to make a go of things for the sake of his heavily pregnant wife (Joanna Page), he’s brought on side for a ‘Song for Christmas’ competition that the headmistress (Pam Ferris) has forbidden them to enter. Things from here descend into good-natured chaos, as the film uses all of the obvious talent show parodies across the audition process and beyond. Tennant gives his best exasperated face, as he’s somewhat unwillingly brought along for Mr Poppy’s crazy plan, and the kids are charming. The joke at this stage is that St Bernadette’s are a talentless bunch. In contrast, the competition from neighbouring entrants is strong, one of which is led my Donald’s estranged twin brother, Roderick. This, of course, means double David Tennant for your money, and there’s rarely a scene in the film that doesn’t feature the actor in some capacity.  It also provides plenty of opportunity for mistaken identity hijinks later on, which is always a winner for young audiences. With the demographic-crossing appeal of a former Doctor in their arsenal, Wootton’s returning teaching assistant is used purely to entertain the young-uns, and results are mixed. Given that I’m well over the age his fart and poo jokes are aiming for, I’ll leave my criticism as vague as that. That said, nothing in this film insults anyone’s intelligence, and there’s actually a good mix of jokes suitable for all, but designed to hit different people with varying intensity. The eventual talent contest is shown almost in its entirety, and is an unexpectedly razor sharp parody of various light-entertainment shows airing in the UK right now. There’s a Justin Bieber-esque kid and a group of private school children singing about poverty, just to give you a taste. As you’d expect from a Christmas-themed sequel, semi-improvised by the adults and kids alike, only about half of the film works. But those bits that make you smile and those bits that make you role your eyes are all mixed in together is a mess of entertainingly chaotic family fun, meaning the end is just as strong as the film’s beginning. It’s in no way perfect, and I doubt it’ll become a Crimbo classic, but everyone looks as if they’re enjoying themselves. You probably will, too. Follow our Twitter feed for faster news and bad jokes right here. And be our Facebook chum here.