Yes, 1 (2013) is free to watch on Plex in the UK with no subscription required.

Where can I watch 1 in the UK?

1 (2013) is available to stream on Plex, Rakuten TV in the UK.

Yes, 1 (2013) is currently available to stream on Plex UK.

Yes — it's on Plex

Available to stream now

1 (2013)

Documentary

Is 1 free to watch?: Yes, 1 is free to watch on Plex in the UK with no subscription required.
Where can I watch 1 in the UK?: 1 is available to stream on Plex, Rakuten TV in the UK.
Is 1 on Plex UK?: Yes, 1 is currently available to stream on Plex UK.

1 (2013) on Plex UK — Streaming Availability | WhereToStream | WhereToStream