Latest: Zimbabwe parties begin process to impeach Robert Mugabe

LATEST: Zimbabwe's ruling party has presented a motion to impeach President Robert Mugabe, seconded by opposition party MDC.

Update 1.54pm: Zimbabwe's ruling party has presented a motion to impeach President Robert Mugabe, seconded by opposition party MDC.

Mr Mugabe, 93, is accused of allowing his wife to "usurp" power and of being too old to rule.