London police stand guard near the entrance to the House of Lords at Parliament. (Peter Macdiarmid/Getty Images)

British officials on Tuesday said they were reviewing security plans for two major events in London – a public funeral parade for Margaret Thatcher on Wednesday and the London Marathon on Sunday – in the aftermath of the Boston bombings.

There was no immediate move to raise Britain's current terrorism threat levels, which remain at a heightened state of "substantial" threat. A number of protestors are expected to attend Thatcher’s funeral parade and officials said in a statement that they would have over 4,000 officers on duty to keep the peace. Protestors will still be permitted space to demonstrate so as long as they do not incite violence.

"The right to conduct peaceful protest is a tenet of our democracy, however that right is qualified in that protest does not stray into acts of crime or violence or the instigation of crime or violence," Metropolitan Police Force Commander Christine Jones said in a statement.

While expressing outrage over the attacks in Boston, organizers and government officials involved in the London Marathon -- sent to draw half a million spectators this weekend -- said the best way to honor the memory of those who lost their lives was to go forward with the event and not cave in to fear.

"These are balance of judgments, but we are absolutely confident here that we can keep the event safe and secure,” Britain’s sports minister, Hugh Robertson, told the BBC. "I think this is one of those incidents where the best way to show solidarity with Boston is to continue and send a very clear message to those responsible."