A few guys at my allotment site have recently cut the haulms off their
maincrop potatoes. They give two reasons for this practice:

Firstly, it considerably reduces the risk of infection by blight.
Secondly, it prevents nutrients and plant energy going into the
production of the potato fruit/seeds.

As this is my first year at growing potatoes , I would welcome any
advice/comments as to cutting the haulms off at this time of year and
leaving the tubers in the ground until harvest time.

Ed
(SE England)