Passengers at Heathrow 1, 2 and 3 are being advised to allow ‘plenty of time’ for their journey through the airport as ground handlers go on strike today (Friday).
While unions warned of chaos, the airport played it down and said only a small number of ASIG ground handling staff are planning to join the 24-hour strike.
ASIG provides ground handling services to some airlines at the three terminals.
"ASIG have plans to maintain their service and we will have extra staff available to support passengers with their journey," Heathrow told passengers.
Heathrow is bringing in extra ‘passenger ambassadors’ (dressed in purple) to help minimise any disruption or confusion for passengers.
ASIG is also putting on additional workers.
The strike has been called by the union Unite as part of a long-running dispute with ASIG management over pay.
The union claims a delayed 2013 pay award should have been implemented 14 months ago.
The strike will run until midnight tonight, affecting both departing and arriving flights. Unite said flight check-in will also be hit.
At 11am, a Heathrow spokesman said there had not been any delays as a result of the strike.