I applied online. I interviewed at High Speed Two (London, England) in Feb 2021
Interview
it was a video interview with questions being asked via a pre-recorded video
there were five questions
you have two minutes to record your answers
you can record up to four answers and choose one to submit for each question
you can playback your answers once recorded
There was an initial screening round, a video interview and aptitude test and a final applicant day. The video portion involved a series of questions testing numerical ability and reading comprehension, often formatted to look like incoming emails.