adding power socket to ring

Hi everyone,
I wish to add a single power socket in a cupboard under the stairs for a tumble dryer so it is out of the way.
There is a ring main running in the kitchen which feeds a power socket before running into the cupboard for a 3A fused light switch. The ring then continues out of the cupboard to feed a double socket in the kitchen.
Can I extend this by adding my single power socket after the fused light switch in the cupboard letting the ring continue as it is back into the kitchen power socket?

Any advice appreciated.

Graham.

As a novice, I think there are two main options here:
1. a spur feeding a single socket taken from from the ring at the FCU (3A light switch)
2. extending the ring after the FCU - remove one cable from the FCU and take it to the new socket then connect the socket and FCU with a new section of cable

I think it would be preferable to bring a spur from the ring at the FCU out to an accessible 20A isolator switch outside the cupboard (but not in the kitchen) and then back to a socket in the cupboard. If the dryer catches fire, for instance, you can isolate it without opening the cupboard.

Thanks for the prompt response.
I have easy access to run the cable outside the cupboard so will take your advice on the spur and isolation switch.

Thanks again.