PETER Mullen (Echo, Mar 14) outlines some of the reasons why he feels it so necessary to renew Trident. He misses out, though, the most important reason not to renew Trident: the probable effect this decision will have on the future proliferation of nuclear weapons.

France and China demonstrated their determination to maintain their nuclear arsenals indefinitely when they carried out test explosions in 1995 and 1996, which prompted India to explode a nuclear bomb in 1998, closely followed by Pakistan. Pakistani nuclear technology was later exported to Libya, North Korea and Iran.

Under the terms of the Non- Proliferation Treaty, the five "recognised" nuclear states agreed to "undertake effective measures in the direction of nuclear disarmament". Their refusal to do so has led to the complete failure of the Treaty to prevent proliferation.

Reducing arsenals by a few warheads is meaningless. Britain has 160 "operationally available"

warheads, each one about eight times more powerful than the Hiroshima bomb. How many countries could we devastate with those? Imagine one each for London, Birmingham, Manchester and Newcastle. We have enough to do that to 40 different countries.

The combined nuclear arsenals of the five states are presumably sufficient to extinguish all life on this planet several times over.

Renewing Trident now will not protect us from attack by terrorists or so-called "rogue states". On the contrary, it will increase the risk that more states will acquire nuclear weapons and facilitate the global exchange of nuclear materials and technology.

Delaying the decision, at least till after the Treaty review scheduled for 2010, could have provided the opportunity to make the Treaty work.

Pete Winstanley, Durham.