I am planning to renovate the kitchen. Currently there is a tall
housing containing a single oven. I am planning to replace it with a
housing containing a single oven and a microwave (just a plain
microwave, not a combination one). The existing single oven is supplied
from a cooker supply point, which also powers the hob.

To avoid running an extra cable from the cooker supply point to the
oven housing to supply the microwave, is it permissible in principle to
wire the existing supply cable into the terminals of the single oven,
and then wire the supply lead of the microwave into those terminals
too?

I will consult an electrician anyway, but am curious if the above
scheme is allowed, assuming the existing supply cable is of the
required size to supply both appliances.