Sir – Global warming is certainly a great excuse for pressure groups such as GreenSpeed to express their prejudices. I don’t know about global warming, but I do know that there is nothing new about climate change. Dates are debated, but roughly between 450 and 900AD we had the Dark Ages Cold Period, 900 to 1250AD the Medieval Warm Period (presumably caused by speeding chariots), 1250 to mid 20th century the Little Ice Age (not sure how the Industrial Revolution fits into that).

I also know that a 50mph limit on motorways would lead to disastrous bunching of lorries, cars and vans and the deadliest of driving enemies, boredom, inattention and sleepiness. I doubt if membership of GreenSpeed would include drivers, otherwise they would know this.

Bill Leonard Oxford