How do know when to book security fast track for?!

[coldfeetwarming]

Trying to sort security fast track at Bristol airport for a Lanzarote flight - leaves at 8.30.

How does the time on the security fast track work - I’ve no idea what time it’ll be when I want to go through (at the mercy of the queues &#129315 - but it books at 15 minutes intervals…..

Not sure I can help but fyi they paused fast track at Stansted last week as they were struggling to cope. Same coming back in yesterday.