UK Police are discovering that terrorist Khalid Masood was mentally disturbed.

LISTEN ABOVE: Rachel Smalley talks to UK correspondent Gavin Grey, about the attack.

Four people died when Masood drove a car through crowds of people on Westminster Bridge and stabbed a police officer at Parliament last week.

UK correspondent Gavin Grey told Rachel Smalley there has been a lot of speculation about whether further attacks are planned and whether he acted alone.

"Well the police say yep they believe he did act alone, and they say they do not believe- there's no information to suggest there are further attacks planned."