Mark White, Home Affairs correspondent
"It was just after the thunderstorm started that the crowd started throwing those bottles and other objects at the police," says Mark White.
"There's no let up in the rain, but clearly that's not bothering the protesters who are continuing to stand up to the police line," he adds.
"This was what the Metropolitan Police were very concerned about. They had been trying to mount as low-key a policing operation as possible.
"They know of course that many of these protesters are very distrustful and do not view the police as being a friendly face, so having an overt police presence is difficult for these officers.
"They know that could have the potential for exacerbating the situation, antagonising the crowd, so that's why senior officers decided the low-key approach would be the best approach - but obviously they're not going to stick with that approach if their officers are coming under attack."
Mark White, Home Affairs correspondent
"I would say there are close to four or five hundred protesters in this area of Whitehall at the moment," says Mark White, noting that some are pushing back against the officers.
"Very dangerous scenes here potentially for the protesters and the officers," he adds.
"It had been building for probably the best part of an hour and a half. We noticed a shift in the atmosphere, it took a turn for the worse," he said.
"There was more officers brought in to supplement the officers at the front of Downing Street, but only in the last 20 minutes or so when the officers came under attack did those specially equipped public order trained officers come out."