Hackney carriage (taxis) and private hire related questions

• How can I tell the difference between a taxi (hackney carriage) and a private hire vehicle?
• Can I hail any cab I see?
• If when I'm looking for a cab I see a private hire vehicle dropping someone off, can I use it?
• Is it true that using a private hire vehicle which hasn't been booked is uninsured for the journey?
• What is the cost of using a taxi (hackney carriage)/private hire vehicle?
• What is the cost of travelling from one local authority area to another’s?
• What if I am disabled and using a wheelchair? Does all of this information apply?
• Can a hackney carriage refuse to take me on a journey?
• Who do I contact if I have a complaint about a taxi?