British Special Forces Find Proof Tehran Is Arming Taliban

... leading many to fear the war will break out into a larger regional conflict.

From the Guardian:

Days after Prime Minister Gordon Brown warned President Mahmoud Ahmadinejad
that Britain would freeze the assets of Iran's largest bank to discourage Tehran
from developing nuclear weapons, Whitehall sources revealed that they had
forwarded 'documentation' that the Iranian authorities were supplying enemy
forces in Afghanistan.

The situation is so serious that the UK government is believed to have
asked Russia and India to raise the issue with Tehran, and to emphasise its
wider implications. Evidence found by UK special forces is understood to concern
the supply of the same bomb-making equipment Iran provides to insurgents in
Iraq, namely components for explosively formed projectiles, or EFPs.

Ideological differences between Iran, a Shia Muslim state, and the Taliban,
a Sunni militia, are thought to have been settled in light of the shared aim in
attacking coalition forces.

Britain now has prrof that Iran is behind the devastating attacks on its troops. But, instead of finding this to be reason to further defend its troops, politicians first concern is a wider war.

That is akin to worrying about not wanting to get into a wider conflict with the man who raped your daughter.