Watch below for a video of the attack by Plane Stupid protestor Leila Deen in slow motion.

The business secretary was hit by the green custard as he walked towards a low-carbon economy conference in central London.

To read the full article on the attack click here.

Speaking to the BBC after the attack, environmental activist Leila Deen, who threw the custard, said: "When democracy is failing you have to resort to any means necessary as long as it is peaceful and does not harm other human beings."

There are already calls for increased security around prominent politicians.