I notice you're asking about downloading for an iPhone 4 running iOS 7.1.2 .
For reliable YouTube on an iPhone 4 with iOS 7.1.2, your best bet is Safari . The official app is no longer supported.
BeGambleAware is an independent charity that empowers responsible gambling across the UK.
The charity provides gambling prevention and treatment services for gamblers and affected families through a safe, professional environment.BeGambleAware Official Website