Hiya, these were gloves issued to ATS girls employed on Ack-Ack in the Air Defence of Great Britain.
As you can see they are convertable and can be worn as a mittens or fingerless gloves.
I take the description of these from the official clothing list of the ATS of which I have a copy. I like original source material. The IWM list them differently:
Mittens, sheepskin ATS | Imperial War Museums
But it is the same item.
Nicely maker marked "Thomas Ensor & Sons, Millbourn Port" and dated 1942