The diplomatic crisis over Qatar that suddenly emerged last week is set to last for a prolonged period, with disruption spreading to affect shipping — or it will blow over again just as quickly as it appeared?

Opinion on the reasons for the dispute and its likely effects and length are widely divergent. It is hardly a surprise, given the number of contradictions at play.

Gulf Cooperation Council (GCC) members Saudi Arabia, Bahrain and the United Arab Emirates (UAE), as well as Egypt, broke off relations with Qatar and suspended all land, air and sea traffic, accusing the tiny nation of supporting or funding terror groups — something Qatar denies.

It is not the first time GCC states have taken diplomatic action against Qatar but previous situations have been resolved. Western diplomats too have accused Qatar of funding some Sunni extremists, such as al-Qaida’s branch in Syria. But the same accusations have been levelled against individuals in Saudi Arabia.

US President Donald Trump trumpeted that the GCC action followed his visit to Saudi Arabia, yet his secretary of state, Rex Tillerson, has been seeking to cool the situation and defence secretary James Mattis says Qatar is “moving in the right direction” on dealing with terror links.

It is worth remembering the 9/11 attackers came overwhelmingly from Saudi Arabia. No Qatari was ­involved. Qatar also hosts the largest US air base in the Middle East, housing about 10,000 American troops; it is unclear whether Trump was aware of that fact.

But Qatar was widely reported to have aided the Muslim Brotherhood when it took power in Egypt in 2011 and helped it in Syria, Libya and Palestine, where Hamas operates as an offshoot of the brotherhood.

Extensive Qatari funding of Iranian Shiite militia is reported to have been made after the fighters ­kidnapped and ransomed high-up Qataris who were hunting with falcons in southern Iraq. If Qatar paid an ­alleged $1bn to free the hostages, it would violate United Nations sanctions.

Yemen is reportedly breaking air links with ­Qatar in response to the GCC move, which is perhaps surprising, since it is under bombardment from its former Saudi and UAE allies. But then the Saudis ­accuse Qatar of backing Iranian-allied rebels in Yemen.

So is the row a pretext for Saudi Arabia to get its hands on ­Qatar’s huge supplies of natural gas — held to be the cleaner fossil fuel of the near future as the world’s love affair with oil recedes and Saudi oilfields age? In 2011, the Saudis were able to move their troops into Bahrain “to restore order”.

Qatar has natural links to Iran. The giant gasfields it is exploiting straddle the sea border of the two countries. But it is Oman that has previously staged joint naval manoeuvres with Iran, and the country through which Qatar now needs to ship cargo due to closure of its sea routes.

The links, accusations and counter-allegations go on and on (on both sides) and shipping could be caught in the middle.

However, the immediate conclusions by the Oxford Institute for Energy Studies do not suggest great cause for concern about LNG supplies being cut off.

Qatar is the world’s largest LNG producer, contributing 30% of global supply, but projects coming onstream in the US, Australia and Russia this year are forecast to push supply to more than 30bn cubic metres per annum (bcma) above the 2016 figure.

Closure of the Dolphin Pipeline that supplied 17 bcma in 2015, mainly to Oman and the UAE, is seen as more difficult but unlikely and still liveable with, say the Oxford researchers, who add that routing LNG tankers from Qatar to Europe around the African Cape rather than through the Suez Canal would add to the transport cost and possibly encourage exports to divert to Asia.

However, that would depress Asian LNG prices and incentivise exporters to swing back to Europe.

Other issues include bunkering of vessels and contractual problems arising from frustrated charter­party clauses.

Past actions suggest the dispute will be resolved by diplomatic compromises. If not, it will be interesting to see how many national football teams gather in Qatar for the World Cup in 2022.