Described by Denis Gifford as "cheap but intelligent" and quite a departure for Merton Park, which although for a long time considered of interest merely as a promising early film by director Alan Bridges now enjoys a respectable reputation of its own as an atmospheric piece of science fiction in its own right in which James Wilson does a fine job depicting a hospital sweltering through a night shift experiencing an unseasonable heatwave ably assisted by an excellent score by Bernard Ebbinghouse.
Despite such pulp elements as female aliens in beehives & rubber suits (more prominently displayed in the posters than in the film itself), under the stewardship of Jack Greenwood - who had already provided Joseph Losey with the opportunity to demonstrate nascent potential with 'The Criminal' - 'Invasion' demonstrates the contribution that can be made by the influence of a specific producer; you only need compare this with the glossier but trashier 'Konga', also made at Merton Park but with the grubby fingermarks of Herman Cohen all over it.
Despite such pulp elements as female aliens in beehives & rubber suits (more prominently displayed in the posters than in the film itself), under the stewardship of Jack Greenwood - who had already provided Joseph Losey with the opportunity to demonstrate nascent potential with 'The Criminal' - 'Invasion' demonstrates the contribution that can be made by the influence of a specific producer; you only need compare this with the glossier but trashier 'Konga', also made at Merton Park but with the grubby fingermarks of Herman Cohen all over it.