Sir - Oxford's Lord Mayor is right: Royal Mail's plan to sort Oxfordshire's mail in Swindon is "daft". But it is consistent with RM's hostility towards its workers and our environment since Leighton and Crozier took charge in 2002/03.

Bernard Greenberg's claim "I don't think global warming' is an issue in this case" ignores the thousands of tonnes of climate-changing gases added to our atmosphere by RM's adoption of long-distance lorries.

His question "How else would mail be delivered all over the country" ignores the 11,000 mile rail network linking the OX postcode region with almost every other postcode region.

For 174 years railways carried our long-distance mail. But in 2004 RM replaced modern 100mph mail trains with huge lorries limited by law to 56mph. Within a year it recognised its blunder and reinstated a few mail trains, but it still sends most long-haul mail by road.

RM admits its HGVs are slower at carrying mail nationwide overnight. Instead of returning to rail it has now "solved" the problem by ordering delivery staff to start work later - in Oxford's case by one hour, in some other centres by two hours. Even beforehand, many deliveries were impeded by morning commuter traffic.

Now the later start causes delivery staff to spend even more of their shift stuck in congestion. As well as delaying mail deliveries, the new shifts prevent some staff from finishing work in time to fetch children from school.

In 2004, sacks of undelivered mail were dumped around Oxford, but since then staff have improved performance, exceeded delivery targets and in 2006 nearly won a national RM efficiency award. But Oxford's efficient staff are also well-organised union members.

RM wants to close one of Britain's most efficient mail centres in order to destroy a branch of the Communications Workers' Union.

Hugh Jaeger, Oxford