Yes, Thor is back. Did we really want him? Chris Hemsworth shrugs off the clouds of glory from his James Hunt in Rush to join Natalie Portman and Tom Hiddleston in rubbishing the space-time continuum. Here the “have hammer, will travel” Norse god time-hops to modern London – hapless Greenwich gets the comic-book apocalypse treatment – and tries to save the universe by obliterating everything in sight. Hokum for overgrown kids, accessorised with daft dialogue. But hey, it’s Halloween.