This is the scene on the Parliamentary Estate where an object described as a “huge chunk of stone” has smashed through a car windscreen. It’s unclear exactly what happened, but a co-conspirator tells Guido that within the last 30 minutes a “huge chunk of stone fell off Norman Shaw North”. Fortunately, there are no reports of any injuries. Leader of the House Andrea Leadsom has been spotted on scene along with police and parliamentary authorities. The car is rumored to belong to Northampton North MP Michael Ellis. Very dangerous… 

Evidence of why @UKParliament needs urgent repair. This stone fell off the top of a building. Imagine if this had hit someone. Unthinkable. pic.twitter.com/ERlgPPK9UZ

— Will Quince MP (@willquince) 19 October 2017

UPDATE 13.30: More pics coming in from the scene:

UPDATE 14.17: A parliamentary spokesperson said:

“The main entrance to Norman Shaw North has been closed for health and safety reasons until further notice. The incident is being investigated by parliamentary authorities as a matter of urgency.”