Why is London's mobile phone reception getting worse?

Why is London's mobile phone reception getting worse? Mobile users across London say their mobile service is becoming increasingly unreliable, with reports of slow data speeds, failed connections and calls not getting through. Mobile UK, the trade association representing the UK's major mobile networks, said London's mobile phone connectivity continues to lag frustratingly behind other international hubs. Data commissioned by the BBC England Data Unit found some of the worst areas were Liverpool Street and Covent Garden, where service proved to be extremely slow and unreliable during rush hour but worked normally during quieter periods. So what impact does this lack of connectivity have on Londoners and their ability to earn a living, and what are the reasons behind it?