Dozens of pro-Palestine demonstrators were arrested late last night after activists clashed with police on Whitehall and outside Parliament.

The Metropolitan Police were forced to act after the protest's turnout "significantly exceeded the estimates of the organisers", with protest group the Palestine Solidarity Campaign claiming over 10,000 people had come to demand a ceasefire in Gaza.

The "vast majority" of demonstrators left at the organised time, but when the protest began to spill over its designated bounds, the thousands-strong remainder began to clash with riot police as roads in the heart of Westminster were temporarily shut down.

The Met said 40 people were arrested for "offences including breaching Public Order Act conditions, obstructing the highway and assaulting emergency workers".

The Met said 40 demonstrators were arrested

Police also confirmed that three officers were injured as a result of the fracas, with one officer sustaining a serious injury to the face after a bottle was thrown at her from the crowd.

The Met Police's Westminster division said officers had instigated a condition requiring the protest to end at 8pm - but a few hundred activists stayed past the cut-off, despite being told "number of times by officers that they [were] now in breach of conditions to finish their protest".

A "breakaway group" then made it to Bridge Street - the road leading past Big Ben to Westminster Bridge - and were detained after "continually [refusing] to comply with conditions which required the protest to finish by 8pm" and obstructing the highway.

Police were eventually able to clear the crowd from Bridge Street