Uber can only be successful if it has a growing fleet of drivers willing to ferry people around their local town or city. With this in mind, the company has announced a slew of changes today aimed at appeasing the biggest complaints of UK drivers. Following the US, the app will support rider tipping from tomorrow, making it easier for passengers to reward good service. In addition, Uber will charge riders who force drivers to wait at their agreed pick-up point. From August 22nd, passengers will have to pay 20 pence per minute if they fail to turn up after two minutes.