Christians in the south of Nigeria are failing to help persecuted fellow believers in the north, according to a veteran humanitarian campaigner.

The Boko Haram Islamist insurgency has left around 20,000 dead and caused massive disruption in northern Nigeria and surrounding countries, with around 2.6 million people displaced.

Baroness Cox, who has made numerous aid missions to the country, told World Watch Monitor: "My personal view is that many of those churches are immensely wealthy and I would hope they could do more to help those who are suffering in the north, particularly the internally displaced people who are left.

"They could work with churches [in the north] who know the needs to reach those most in need.

"From a Christian point of view, St Paul said that where one part of the Body of Christ suffers, we all suffer. There is an obligation to help our Christian brothers and sisters."

Lady Cox said that southern churches sent occasional consignments of aid, but a tribal rather than national outlook often prevailed resulting in a "disconnect at every level" between Christians in the north and those in the south.

She also said Nigerian President Muhammadu Buhari is failing to adequately respond to the increasingly frequent attacks by groups of armed Fulani herdsmen on Christian villages and leaders in the country's Middle Belt. She suggested that the lack of "robust reprisals" could be linked to him being an ethnic Fulani.

Nigeria's Federal Government has pledged to establish cattle ranches to resolve the frequent clashes between herdsmen and farmers, which President Buhari has attributed to "poverty, injustice and the lack of job opportunities". Other analysts cite climate change and desertification as factors. However, researchers such as Open Doors' Yonas Dembele says the attacks amount to the ethnic cleansing of Christians.

Lady Cox said the attacks by Fulani herdsmen were "deeply disturbing" and had an ideological aspect because eye-witnesses reported them shouting "Allahu Akbar" as they carried out their attacks. She said the herdsmen passed through the Sharia-run states in the north without carrying out attacks. She suggested Boko Haram might have a role in training them, adding: "There's a lot of concern [the cleansing by Fulani militias is] an extension of the Islamisation of Nigeria."