There have been efforts to play down his decision to not renew his contract in August, four years before the museum’s scheduled opening.

When asked for their reactions, individuals ranging from the head of a public arts body to a senior curator at M+ all said Nittve’s announcement was widely anticipated, and that it would not derail the project.

The latter is something that Nittve himself is keen to stress. In an interview, he points out that he is not really leaving. His current contract, which expires on January 9, 2016, will be replaced by a new one that will see him showing up for work as a consultant for one week each month in Tsim Sha Tsui. “I will be doing this for at least a year, maybe longer,” he says. “M+ is a team effort but it is also very much my brainchild. I’ve been here five-and-a-half years. I want it to have a happy ending,” he says.

He says his decision to not renew his current contract is a recent one. “Michael did not know. I made this decision, as one does with decisions about what’s important in life, during my sabbatical in August,” says the 62-year-old Swede.

“I am not doing this for health issues. I am not doing this because of the new CEO, Duncan Pescod. And I am not doing this because I have a new job,” he says.

What it boils down to is the horrendous delay in construction. The WKCD was first proposed by the Tung Chee-hwa government in 1998. Seventeen years later, hardly anything has been built on the 40-hectare site and key completion dates keep being rolled back.

“When the opening date of M+ was 2017, it was possible to stay for that. But now that it’s going to be 2019, I really cannot commit to another four years in my current role and it would be much worse for everyone if I leave in the middle of those four years,” he says. Setting up M+ is the most challenging job he has ever done and at his age, he decided there were other things in life that mattered more, he says.

Like Lynch, he admits to feeling frustrated by politicians who level unconstructive criticism at West Kowloon and M+, on issues such as having foreigners in leadership roles. “The team I built up at the Tate Modern included several non-British experts. It doesn’t matter where you are. When you want to build a world-class museum, you need an international team,” he says, recalling his time as the founding director of the London institution.

The fact that so many people in Hong Kong are disenchanted with West Kowloon is not conducive to a great working environment, he says, but that’s not the reason why he’s stepping down. He also dismisses concerns about the artistic freedom enjoyed by his team, saying he has not come across any attempt by Beijing to intervene in M+ operations, where the acquisition policy may be deemed politically sensitive.

“I am not looking for a job. I want to live in my mountain house in Sweden and write more,” he says.

He gazes longingly at the wallpaper on his smartphone – a photograph of a two-storey house with a pitched roof surrounded by snow, a prototype for Christmas cards. This is the house his architect wife designed, and it is near Åre, one of Sweden’s top ski resorts.

“The longest I’ve stayed in it is three weeks. I really look forward to spending more time there,” says the keen skier.

The once-a-month commute to Hong Kong simply requires him to take a short flight from Östersund to Stockholm, and then a 10-hour direct flight to Hong Kong. “It’s going to be very doable,” he says.

He has a lot of confidence in Pescod, a veteran civil servant, and his ability to make West Kowloon happen, and he cannot see how M+ could possibly suffer any more significant delay. “Once we started work on the foundations, any problem that could pop up would have popped up,” he says. The foundations were completed in September.

He also feels secure about the artistic foundation he’s laid at M+. The team has already acquired around 65 per cent of the collection that will be in place by the time the museum opens in 2019 and there’s no way of undoing that, he says. His only concern, he says, is whether the authority can hang on to other senior people at M+. In April, Tobias Berger quit his job as curator at M+ to become the head of art for the project to revitalise the former Central police station in Hollywood Road, in Hong Kong’s Central district.

“The [West Kowloon Cultural District Authority] has to make sure they don’t leave,” Nittve says.