Originally Posted by
KARFA
I have a feeling that you can't use the connections security in T5B/C unless your flight is departing from those buildings, I seem to remember reports of that before - and there is a significant risk that connections security in the satellites may not be open on the day you try this.
C security is often closed now, but B is back to normal, at least until early evening. They do allow it to be used for any connection, but only if you make it clear you know about the existence of the tunnel (and how to find it). Their script is designed for the clueless majority but there’s no specific rule against using it for any I-I connection (obviously it can’t be used for I-D as there’s no UK border post there).
The A380 gates in B are definitely used, but you’re right it’s not hugely common. They tend to move the additional security equipment (and staff) over to C for those flights instead.