The city of Sheffield is set for an invasion by mutant “porn star” fleas.

The fleas are currently in the midst of their breeding season with males rushing from female to female, with the female fleas giving birth at an incredible rate.

The number of fleas means homes and offices can quickly become infested with the creatures being carried into homes on cat and dog fur.

The fleas then make their homes in carpets and furniture and can go on a mating frenzy, leading homes to be quickly overrun with the bugs which can bite, leaving itchy spots on humans.