Sir – Bus and coach deregulation in 1986 had mixed results. In cities it unleashed “bus wars” between new and established operators.

Buses reduce congestion but bus wars increase it. This spawned a misguided prejudice that led Oxfordshire politicians short-sightedly to pedestrianise Cornmarket in 1999 and remove Queen Street’s bus stops in 2009. This dismembered vital bus connections and showed cross-party political indifference to disabled or elderly people.

However, deregulation transformed some coach fares and frequencies. The Espress and Stagecoach between them now run 150 Oxford-London trips daily.

With different London destinations, they partly complement each other, rather than fighting for identical markets.

But should inter-city public transport growth rely on coaches? A well-loaded diesel coach has higher emissions per passenger than a well-loaded diesel train.

Daniel Scharf (Letters, August 11) advocates running coaches on LPG and raising their speed limit to 70mph. But the two-year-old Oxford Tube fleet is unlikely to be renewed for years, higher speeds would increase fuel use per passenger and reduce safety, and congestion delays coaches whatever their fuel.

By contrast, in 2012 Worcester–Oxford– Paddington trains will be enhanced and 287-seat, 125mph Adelante trains may return.

In 2013, Chiltern’s Marylebone line will double Oxford–London rail capacity. In 2016 Oxford–Paddington trains will be electrified, reducing their carbon footprint by 30 per cent. In 2017, Crossrail will reduce the number of passengers having to use Paddington station.

Between cities, only rail can provide high enough capacity with low enough emissions to save our environment.

Hugh Jaeger, Oxford