Does the UK do Cyber Attacks?

The short answer is that most countries engage in covert cyber operations, i.e. cyber warfare, also known as nation-state hacking or cyberterrorism. Covert cyber operations have existed for as long as computers have existed, indeed, covert operations kick-started the invention of the computer. When the Bletchley Park codebreakers needed help in cracking the German Enigma cyphers during World War II they invented the first programmable computer, Colossus. The existence of Colossus was kept hidden from the public for many years after the war.

The UK's National Cyber Security Centre (NCSC) makes a big deal about how the UK is defended from cyber attacks, however, what about cyber offensive operations. Does the UK do cyber attacks? Well, a job advert posted at the end of April 2021 provides a pointer:

The job to work as Director General Q at the UK’s Secret Intelligence Service is to work with technology to help protect the UK. Notice the phrase proportionate cyber activity, what could that mean? Maybe it is suggesting not only cyber defensive activity but when required cyber offensive activity. So, does the UK do cyber attacks? We'll often hear of the UK defending itself from nation-state cyber attacks, and it is often said that attack is the best form of defence, maybe that is proportionate cyber activity.