Nine months ago they were greeted as heroes, posing on their armoured vehicles for selfies with civilians overjoyed at their liberation from a moribund, corrupt, and violent dictator who had plunged the country into economic misery. 

But on Wednesday night Zimbabwean troops were back on the streets of Harare – with bayonets fixed and in armoured cars to impose order with a blunt force that brought back unpleasant memories of Robert Mugabe’s reign. 

And the fragile hopes that Zimbabwe’s first elections since Mr Mugabe was overthrown would be peaceful went up in a pall of black smoke and tear gas.

Police said three people were killed in several hours of clashes between opposition supporters and…