It's a mistake to conflate cyclists filtering through traffic and undertaking.
The Highways Code specifically mentions that motorcycles do this also Rule 88 [1] and tells drivers that that they should be aware of other road users including cyclists doing this too [2] Rule 21.
The Highways Code specifically mentions that motorcycles do this also Rule 88 [1] and tells drivers that that they should be aware of other road users including cyclists doing this too [2] Rule 21.
[1] https://www.gov.uk/guidance/the-highway-code/rules-for-motor...
[2] https://www.gov.uk/guidance/the-highway-code/road-users-requ...