What actually drives timing
A provider can only pay after it has approved the application and completed its checks. Banking cut-off times and Faster Payments availability then decide when money lands. Apply late in the day or on a weekend and payment may wait.
Marketing is not a promise
Phrases about instant or same-day funds describe a possible path, not an entitlement. Extra identity or affordability checks can delay payout even after a “decision in principle”.
If the bill cannot wait
See the emergency borrowing page for product types and alternatives. Speed is a poor reason to skip total-cost and affordability checks.