It is, however, a sign of complete desperation.
There has been, for some good time, a talent deficit at the heart of the Tory Party. Not only that but Sunak doesn't know who he can trust. That he has had to turn to a former PM who isn't elected to be Foreign Secretary says a lot, it will also say a lot to Tory MPs of which there are many, that would have supported Sunak but now might think why bother if a position can go to the likes of Cameron.