Is it safe to Tee in?

Just moved into a new (old) house and the only sensible access point for adding a spur or tee for a double socket, is from the wire in the airing cupboard that feeds the programming box switch. Would it be safe to tee into this cable before it reaches the control box, with a 30A junction box and run a spur from there. The max load on the sockets would be bedside lights and occasionally the vacuum cleaner?
Many thanks

[AlanE]

The existing accessory in the airing cupboard is it wired into the ring system or is it a spur?

If part of the ring then it MAY (remember I cannot see situation so cannot comment for certain) be safe to fit junction box and a double outlet but if it is a spur itself then no as you are only permitted two outlets on any spur.

Your comment regarding proposed loading is irrelevant. Two table lights today but a 13Amp outlet is designed to take a fire and next year the use of the outlet might change because a fire is needed in that location!