Both attacks targeted religious minorities in their houses of worship. The perpetrators did not carry out the attacks because of local issues, but because of delusions about a global clash of civilisations.

Intelligence failures inevitably lead to reviews, structural changes and changes in the focus of the agencies involved. But should the directors of these organisations or their responsible ministers be held accountable?

In New Zealand, security intelligence is the responsibility of the New Zealand Security Intelligence Service - the equivalent of our ASIO - while in Sri Lanka it is the State Intelligence Service.

The New Zealand service, formed in 1956, is the country's primary intelligence agency. It's responsible for informing and advising on matters related to national security (including counterterrorism and counterintelligence) and foreign intelligence (because New Zealand doesn't have a foreign intelligence service).

Its director-general is Rebecca Kitteridge, a public servant who was cabinet secretary from 2008 to 2013, and who was seconded for six months to the Government Communications Security Bureau (New Zealand's equivalent of our Australian Signals Directorate) to review its compliance systems and processes. She became head of the New Zealand Security Intelligence Service in May 2014.

The responsible minister is Andrew Little, who, when a Labour-led coalition government formed in October 2017, became Justice Minister, Minister for Treaty of Waitangi Negotiations and Minister in charge of the intelligence agencies.

In Sri Lanka, the State Intelligence Service, formed in 1984 (as the National Intelligence Bureau), is also tasked with collecting both internal and external intelligence, and is part of the Defence Ministry.

Nilantha Jayawardena has been its director since March 2015, while also being a senior deputy inspector-general of the Sri Lanka Police. He seems to have had political patronage because he joined the police as an assistant superintendent and is now the youngest-ever officer of his rank in Sri Lanka.

Jayawardena has a commerce degree, a business management postgraduate degree and a diploma in conflict resolution - but doesn't seem to have any relevant police or intelligence qualifications.

The responsible minister is Maithripala Sirisena, Defence Minister and President of Sri Lanka since January 2015. Soon after he became President, Sirisena appointed Ranil Wickremesinghe as prime minister. In October 2018, after the two men fell out, Sirisena fired Wickremesinghe and prorogued Parliament, causing a constitutional crisis. He then appointed former president Mahinda Rajapaksa as prime minister. The country's supreme and appeals courts ruled against Sirisena's decisions, and he was forced to re-instate Wickremesinghe as Prime Minister in December 2018.

How do intelligence failures come about? Thomas Copeland, an academic expert on the topic, says they include one or more causal factors: organisational obstacles; psychological and analytical challenges; problems with warning information; and failures of political leadership. I would add "complacency" and "obsessive focus on other targets".

In the New Zealand case, intelligence failed to recognise the potential danger from extreme-right-wing actors, such as Brenton Tarrant, despite the example of right-wing terrorist Anders Breivik, who killed 77 people in Norway in 2011. It was also common knowledge that, in 2018, Britain and the United States arrested more right-wing extremists planning terror plots than Islamist extremists. Intelligence agencies should also have acted on the warning from Tarrant's gun club.

In Sri Lanka, Indian intelligence provided three warnings of imminent attacks on churches before the Easter attacks. They were not acted on because senior police failed to heed them, and the Prime Minister was out of the loop because of his feud with the President, the responsible minister. This was not so much a failure of intelligence as a failure of the command system.

The intelligence failure was the State Intelligence Service's lack of awareness of the dangerous extent of Islamic State-related activity in the country.

Should leaders be held accountable? The New Zealand minister, Little, is unlikely to accept any blame. The Westminster tradition of ministerial responsibility is seldom practised these days in Australia or New Zealand. Kitteridge has been in the job for nearly five years and should probably be replaced by a career intelligence manager and moved to another public service job.

Sri Lanka's minister, Sirisena (who is also President), is likely to shift the blame and unlikely to surrender the defence portfolio that gives him control of the military, police and intelligence.

State Intelligence Service director Jayawardena should go because he lacks intelligence experience and was implicated in the costliest day of terrorist attacks in Sri Lanka's history. He should be replaced by an experienced professional intelligence officer; one who doesn't share the usual Sinhalese obsession with threats from Tamils and Hindus.

Those ultimately deemed responsible for the intelligence failures should be thankful they are not in Saudi Arabia, where such failure can result in public beheading!