So-called Islamic State (IS) will never be defeated unless the corrupt conditions that help it to thrive are addressed, a new report claims.

Transparency International accuses western governments, including the UK and the US, of ignoring corruption as a major driver towards terrorism, notably in the Middle East.

It calls on them to press far harder for accountability in military budgets.

The report comes as Iraqi forces advance on the IS stronghold of Mosul.

The report, entitled The Big Spin, argues IS took advantage of corruption to radicalise and recruit people, presenting itself as the antidote while ignoring its own dishonest activities.

“Corruption is a rallying cry, an enabler and a key modus operandi for IS,” said Katherine Dixon, director of Transparency International Defence and Security.

“The failure to grasp this undermines efforts to tackle the rise of violent extremism.

“The international community expends great efforts tackling the ‘ideology’ of groups such as ISIS, focusing on the religious rhetoric they produce, yet completely ignoring the material circumstances in which they thrive.”