South London Healthcare NHS Trust had to take down it website after it was hacked overnight on Tuesday.

The word “hacked” appeared in red above a message written in Arabic with a sword on a black background.

The trust said it is investigating how this happened and thatthe group responsible "appears to target websites at random and there is no reason why the [trust] site was targeted.”

"The hacking of the site has not compromised security of the trust’s IT systems, which are protected by the very secure national NHS network,” a statement said.

“The website is hosted externally and is completely separate to systems used in the hospital.”

The BBC reported that its Arabic Service said the inscription was the “shahada”, the one-line declaration of faith which needs to be said by those converting to Islam.

The Arabic Service also noted that the inscription and sword on a black background are “similar to an insignia known to be used by some Islamic extremist groups.” The website is now back online.