Sir - Hugh Jaeger's letter (March 7) raises two challenges.

First, he refers to the rebuilding of junction ten on the M40 as if it were a success. In fact, it is a catastrophic failure because it sets the two major traffic flows - west off the M40 and east on to it - against one another and inevitably creates huge queues back on to the carriageway and local road networks.

I am not sure whether this was a catastrophic miscalculation on the part of Highways Agency "experts" or a deliberate attempt at traffic calming. What it is not is a helpful improvement; it is the reverse.

Turning to Mr Jaeger's challenge to me to give evidence of my claim that the Shipton-on-Cherwell site is unsustainable in transport terms, this is simple. Something like 5,000 homes at Shipton-on-Cherwell will lead to approx 12,500 people seeking to leave their houses in the morning and returning in the evening.

The evidence will be found by asking the question "how many trains will it take to serve the morning out-commute from this proposed eco-town?". I think the answer is "a huge amount more than the network can currently provide". I challenge the experts to prove me wrong.

Keith Mitchell Leader Oxfordshire County Council