British forces have been savaged by ill-judged and excessive defence cuts

David Cameron says the fight against the Islamic State is a struggle that will last years, not months.

He has committed Britain to a leading role in Iraq and has suggested our forces will expand their operations into Syria.

But our forces have been savaged by ill-judged and excessive defence cuts.

Even our limited role in Libya for just a few months in 2011 left us severely over-stretched, according to RAF and Navy chiefs.

And that was before huge new cuts to both services, as well as the Army.

Cameron has ruled out boots on the ground in the fight against Islamic State.

Such public statements are grossly irresponsible and serve only to encourage the enemy by signalling our weakness. Nor does this policy make military sense.

How can we depend totally on local forces that have repeatedly proven their inability to halt the Islamic State’s advance?

We must be ready to attack with our own ground forces, if it is necessary.

The forces we commit must be able to sustain an operation over many years.

Yet following repeated cuts our ability to do so is in doubt. These must be reversed and the plan to rely so heavily on part-time soldiers abandoned.

Cameron says he has learnt lessons from Iraq and Afghanistan. But has he learnt one of the most crucial ones that fighting a war with too few troops is ineffective and costs British soldiers’ lives?