The most current document is:
Inclusive Mobility - [Department of Transport, 2021]
It draws on other key sources (LTN 1/20, TSRGD, Equality Act 2010, ...)
[1.3] "The overall objective of this guide is to enable practitioners to provide an inclusively designed public realm, and through that help achieve social inclusion."

An older Scottish equivalent is:
Roads for All - [Transport Scotland, 2013]

Comments here are based on the DfT document.
The TS document will be reference where there is a significant difference.

2.1 Engagement
"Effective engagement enables designs and schemes to be tested with end-users, maximising inclusivity."

3.1 Definitions
"In designing or modifying facilities the aim should be to be generous in the allocation of space."
[Hopefully this is intended to mean generous to pedestrians.]

The main requirement for pedestrians in urban centres is unobstructed, level footways.
Section 3 includes extensive data of wheelchair measurements without drawing any general conclusions.
This seems to be an unhelpful approach. A more practical guidance would be to specify dimensions of suitable routes.

4.2 Width and height clearance
In summary, both documents agree:
• The normal minimum width of a footway is 2.0m
• The absolute minimum width is 1.5m
(In extreme cases, this can be reduced to 1.0m over a maximum distance of 6.0m)

- [Dft & TS, old?]

Inclusive Mobility- [Transport Scotland, 2013]

[2021] 4.2 Width and height clearance
This repeats the 2.0m and 1.5m widths from Roads for All.
It adds: "Where there is an obstacle, such as lamp columns, sign posts or electric vehicle charging points, the absolute minimum width should be 1.0m, but the maximum length of such a restricted space should be 6 metres."
Comment - The absolute minimum of 1.0m is undesireable and should be avoided.
It is not acceptable for temporary occupation.
(This also discussed gradient and crossfall.)