The sister of the London Bridge terror mastermind is believed to have been sacked from Heathrow amid questions about staff vetting at the airport. Britain’s biggest airport carried out an investigation with security services into the sister of Khuram Butt, who massacred revellers in the capital last month.

Butt, 27, was known to M15 as a key figure in extremist group al-Muhajiroun and appeared in the Channel 4 documentary The Jihadis Next Door. His older sister, Haleema Butt, 28, got a job working security at Heathrow two months before the attack. A source has revealed the mother-of-two had her employment terminated as a result of the probe.

The airport announced Haleema and husband, Usman Darr – who also worked on security – were initially suspended. Usman, who had worked at Heathrow for a number of years, is believed to be still suspended.