The NCSC is working to fix a critical PHP security flaw affecting almost 70% of websites, leaving 32 UK Government services offline and four partially unavailable as organisations worldwide scramble to apply security updates No 10 said no large UK public-facing critical services have been affected, but some ‘limited’ Government websites have temporarily gone dark. Key points and original sources are listed below.

• The NCSC is working to fix a critical PHP security flaw affecting almost 70% of websites, leaving 32 UK Government services offline and four partially unavailable as organisations worldwide scramble to apply security updatesS1

• No 10 said no large UK public-facing critical services have been affected, but some ‘limited’ Government websites have temporarily gone dark.S2

• Cybersecurity chiefs warned UK organisations that a ‘critical security issue’ had been discovered in the programming language PHPS3

• Downing Street did not provide details of which websites are affected.S4S5