A Heathrow spokesman said:
There are some longer queues than normal in the terminals, but we have spoken to border force and they are putting on extra staff.Obviously we want to sort the issue out but not risk the integrity of the border controls.
More top news
This year's Pride in London event will include a minute's silence to commemorate the victims of the Orlando shooting.
The London property market is expected to be the hardest hit as buyers sit it out to see how the economy will be affected.
The former London mayor paid tribute to David Cameron just hours after the Prime Minister announced his resignation.