Four police officers and a member of police staff were injured during a spontaneous anti-austerity protest against the new Tory government.
Riot police clashed with frustrated crowds outside Downing Street just a day after David Cameron declared victory at the ballot boxes.
Seventeen people have been arrested for a range of offences including public order, violent disorder and assaulting a police officer.
Meanwhile, damage caused to The Women of World War II monument on Whitehall, just a stone’s throw from a VE Day celebration concert at London’s Horse Guards Parade, was condemned by Downing Street as “despicable”.
The words “F*** Tory scum” were scrawled in red near the bottom of the large memorial and police have now appealed for witnesses.
A Downing Street spokesman said: “Spraying graffiti on war memorials is a despicable display of disrespect for those who fought and died for their country, particularly at a time when the whole nation comes together to commemorate the 70th anniversary of VE Day.”
Four police officers and one member of police staff have been injured policing this protest.
Hundreds of anti-Conservative protesters, some holding placards reading “I pledge to resist” and “Stop the cuts”, took part in the rally yesterday.
It is believed to have started outside Conservative headquarters, where just over 24 hours ago Mr Cameron gave a rousing speech to party activists about their unexpected win.
Police were pictured holding batons as they confronted the crowds and controlled what they called an “unplanned” demonstration.
In Cardiff, singer Charlotte Church joined a similar rally at the Aneurin Bevan statue in Queen Street, where she was pictured carrying a placard which read: “I’m mad as hell and I’m not going to take it any more.”
A Scotland Yard statement said: “Four police officers and one member of police staff have been injured policing this protest. Two received hospital treatment.
“One officer was treated for a suspected dislocated shoulder and a member of police staff was treated for a cut lip after being struck by an object. Three other officers were assaulted and did not require hospital treatment.
“There are no reported injuries to any members of the public.”
Chief Superintendent Gerry Campbell added: “The vast majority of those protesting did so peacefully. However a small minority were intent on causing disorder and engaged in violence, injuring five officers and staff - two of which required hospital treatment. Our best wishes are with those officers and staff at this time.
“We have launched an investigation into criminal damage to the Women in World War II Memorial. This is particularly abhorrent considering we are celebrating the 70th anniversary of VE Day.
“I am appealing to anyone who witnessed the criminal damage taking place or may have information regarding those involved to contact Police on 101 or Crimestoppers anonymously on 0800 555 111.”