The airline initially stated seven Britons and one Irish national were on board the Boeing 737 MAX 8 aircraft, which went down after departing Ethiopian capital Addis Ababa.

However, a further two passengers were found to be dual nationals travelling on different passports, the BBC reports.

“We can now sadly confirm at least nine British nationals were on board flight ET 302,” said the Foreign Office in a statement.

“Our staff at the British Embassy in Addis Ababa are continuing to work with the relevant authorities in Ethiopia to obtain further information.

"We extend our deepest condolences to all those who have lost loved ones and those affected by this tragic event.”

Boeing’s 737 MAX 8 aircraft, which entered commercial service in May 2017, has come under intense scrutiny since Sunday’s crash, Ethiopian Airlines flight ET 302 being the second 737 MAX 8 aircraft to come down shortly after take off.

Sunday’s incident, in which all 157 on board the aircraft (149 passengers, eight crew) were killed, followed that of Lion Air flight JT 610, which crashed into the Java Sea in October last year after taking off from Indonesian capital Jakarta.

While investigations into that crash are ongoing, initial findings suggest a new anti-stall system forced the aircraft’s nose down which the pilots were unable to override. There has been no suggestion at this stage a similar fate befell Ethiopian Airlines flight ET 302.

The MAX 8 is the latest version of Boeing’s massively popular 737 range, which is capable of operating a wide range of short to mid-haul routes up to around 7,000km.

By the end of January, Boeing had delivered more than 350 737 MAX 8 aircraft following more than 5,000 orders.

In Europe, Tui currently operates 15, Norwegian 18 (16 owned and two leased) and Icelandair three. Ryanair has 135 737 MAX 200 on order, a variant for which it will be launch partner.

The US Federal Aviation Authority (FAA), which is co-leading the investigation into Sunday’s Ethiopian Airlines crash, has issued a “continued airworthiness notification” confirmed it believes the 737 Max 8 to be airworthy.

It has, however, requested Boeing submit design changes by next month. Boeing says it will issue a software update “in the coming weeks”, which it stressed was “designed to make an already safe aircraft even safer”.

The CAA confirmed on Monday (March 11) there are currently five 737 MAX 8 aircraft registered in the UK, with another due to come into service this week.

“The FAA is responsible for certifying all Boeing 737 Max 8 models and it is the European Aviation Safety Agency (Easa) that validates this certification across the EU, including the UK,” said the CAA in a statement.

“The UK Civil Aviation Authority is liaising very closely with the Easa as the facts of this incident are established."

Ethiopian Airlines, Cayman Airlines, Brazil’s GOL and Aeromexico have grounded their 737 MAX 8 aircraft, while the Chinese, Indonesian and Singaporean aviation authorities have ordered operators ground theirs.

Norwegian said its 737 MAX 8 aircraft would continue to operate as normal.

Tomas Hesthammer, Norwegian’s director of flight operations, said: “Our thoughts go out to everyone affected by this tragic accident. All of our Boeing 737 MAX aircraft are operating as normal. We are in close dialogue with Boeing and follow their and the aviation authorities’ instructions and recommendations. Our passengers’ safety is and will always be our top priority.”

A Tui spokesperson said: “Tui Airways remain in close contact with the manufacturer and regulatory authorities and we have no indication that we cannot safely operate our 737 MAX aircraft. The safety and wellbeing of our customers and staff remains our primary concern.”

Ryanair chief executive Michael O’Leary told the Irish Independent the airline wasn’t preparing to take any immediate action, adding: "We need to wait and see what the outcome of the investigation will be."

Ryanair has 137 737 MAX 200 aircraft on order, with an option on a further 75.

The 737 MAX 8 is an attractive prospect for airlines, offering significant improvements in fuel efficiency.