London attack fuels calls for tighter Westminster security

The Carriage Gates through which Khalid Masood entered the grounds of parliament.Demands are growing for security around the houses of parliament to be enhanced as police seek to establish whether the terrorist who attacked Westminster had scouted the area for weak points.The footage shows the Carriage Gates, through which Khalid Masood entered the grounds of Westminster Palace where he stabbed PC Keith Palmer to death, left unguarded for several minutes.