‘Beefless beef burgers with blood’ might sound like a line from Dr Seuss but it actually describes a new vegan food product by Silicon Valley’s Impossible Foods. Composed of genetically engineered proteins and plant-based matter, the ‘Impossible Burger’ is meant to look, smell and taste like the real thing.

But documents obtained via Freedom of Information requests by the ETC Group have put a question mark over whether the burger is safe to eat.