Is the Russian Revolution something celebrate or regret?

For some on the left of politics, this weekend wasn't just a chance to mark the anniversary of the failed gunpowder plot here in Britain, but also events in Russia 100 years ago when Bolshevik revolutionaries led by Lenin seized power and ushered in seven decades of communist rule.

For critics, that's something to regret, not celebrate.

Elizabeth Glinka went to one event in London to find out more.