http://www.legislation.gov.uk/uksi/2017/498/madeThe Air Navigation (Restriction of Flying) (Westminster Bridge, London) (Emergency) Regulations 2017King's Printer of Acts of Parliament2017-04-05 The Air Navigation (Restriction of Flying) (Westminster Bridge, London) (Emergency) Regulations 2017RegulationsThe Air Navigation (Restriction of Flying) (Westminster Bridge, London) (Emergency) (Revocation) Regulations 2017reg. 2reg. 1