The plane was a British Airways flight BA38 from Beijing to London, the airline said.
It is not clear if anyone has been injured during the incident. Emergency services are currently at the scene.
The incident happened as Prime Minister Gordon Brown was due to leave Heathrow for China and India. His flight was delayed because of the incident.
Benazir Bhutto had been addressing rallies in many parts of Pakistan
Pakistani former Prime Minister Benazir Bhutto has been assassinated in a suicide attack.
Ms Bhutto had just addressed an election rally in Rawalpindi when she was shot in the neck by a gunman who then reportedly set off a bomb.
At least 15 other people died in the attack and several more were injured.
Shannon Matthews has been missing for three weeks
Missing West Yorkshire schoolgirl Shannon Matthews has been found alive, it has been reported.
West Yorkshire Police are yet to confirm that she has been found but said they were looking reports the nine-year-old had been found
Prince Harry has been fighting the Taleban on the front line in Afghanistan, the MoD has confirmed.
Harry, 23, who is third in line to the throne, has spent the last 10 weeks serving in Helmand Province.
