The Gatwick incidents last December certainly accelerated measures that were already discussed and were expected for later this year. In particular, the runway protection zones of protected aerodromes now measure 5km in length by 1km in width.
The amendment is published at: http://www.legislation.gov.uk/ uksi/2019/261/made.
For detailed understanding of the ANO 2018 and ANO 2019 amendments combined, you may refer to CAP1763 . https://publicapps.caa.co.uk/modalapplication.aspx?appid=11&mode=detail&id=9002&mc_cid=9acfff3120&mc_eid=734adba27f