Flights have resumed at Heathrow Airport as its chief executive apologised to stranded passengers and defended the response to an "unprecedented" loss of power caused by a substation fire.Thomas Woldbye described the blaze which knocked out an electricity substation in Hayes late on Thursday evening as "as big as it gets for our airport" and that "we cannot guard ourselves 100%".The Metropolitan Police said they are not treating the incident as suspicious while the London Fire Brigade announced

Flights have resumed at Heathrow Airport as its chief executive apologised to stranded passengers and defended the response to an "unprecedented" loss of power caused by a substation fire.Thomas Woldbye described the blaze which knocked out an electricity substation in Hayes late on Thursday evening as "as big as it gets for our airport" and that "we cannot guard ourselves 100%".The Metropolitan Police said they are not treating the incident as suspicious while the London Fire Brigade announced its investigation will now focus on the electrical distribution equipment.