Harland and Wolff, the Belfast shipyard that built the Titanic, will be put into administration on Monday after its bankrupt Norwegian owner failed to find a buyer, as a union supporting its workers called for the yard to be renationalised.

The shipyard, whose towering yellow cranes dominate the Northern Irish city’s skyline, has been occupied by workers fearful for their jobs since last week. They said on Monday they would block administrators from entering the site.

“There has been a series of board meetings, the result of which is that administrators will be appointed over the course of the day,” a Harland and Wolff spokesman said.

The business was put up for sale last year by Norwegian parent Dolphin Drilling, which filed for bankruptcy in June. The Norwegian administrator of Dolphin Drilling did not immediately respond to a request for comment on Monday.

Opened in 1861, Harland and Wolff employed more than 30,000 people in its Second World War heyday and remains a potent symbol of Belfast’s past as an industrial engine of the British Empire.

Curse of the Titanic: What happened to those who survived? Show all 6 1 /6 Curse of the Titanic: What happened to those who survived? Curse of the Titanic: What happened to those who survived? 2663304.jpg The SS 'Titanic' leaves Belfast pulled by tugs, shortly before her disastrous 1912 maiden voyage Getty Images Curse of the Titanic: What happened to those who survived? 5282561.jpg The actress Dorothy Gibson made it off the 'Titanic' but fell into a bad marriage and a terrible fate at the hands of the Nazis Randy Bryan Bigham Collection Curse of the Titanic: What happened to those who survived? 5283869.jpg Some of the Titanic's 705 passengers made it on to lifeboats Rex Features Curse of the Titanic: What happened to those who survived? 5283866.jpg Jack Thayer seemingly personified the word 'survivor' having jumped from a rail into the sea as the ship sank Robert Maguire Curse of the Titanic: What happened to those who survived? 5283867.jpg An anxious crowd in New York awaits the survivors Rex Features Curse of the Titanic: What happened to those who survived? 5283865.jpg Survivor and silent-screen star Dorothy Gibson made a film of the disaster with her lover - the wealthy, but married film pioneer Jules Brulatour Randy Bryan Bigham Collection

It has been in decline for over half a century, however, and now employs just 130 full-time workers, specialising in energy and marine engineering projects.

The workers locked themselves into the yard last week and are taking turns occupying key buildings in a bid to take control of a process they fear will deprive them of their jobs.

Susan Fitzgerald, a official at trade union Unite, called on Monday for the British government to take the yard back into public ownership, echoing a letter given by members to new the new prime minister, Boris Johnson, last week.

The shipyard’s yellow cranes have been a staple feature of Belfast’s skyline for a generation (PA)

“In the absence of politicians and other people creating a space for a solution to be found – we have already advanced what we think it is, that’s renationalisation,” she said.

Ms Fitzgerald said she was concerned by media reports that the yard might be sold by administrators without liabilities such as pensions and workers’ contracts, adding: “This would be a cynical move designed to jettison jobs and workers.”

Harland and Wolff was state-owned from 1975 to 1989.

A British government spokesman said the yard’s fate was a commercial issue.

Titanic sank due to enormous uncontrollable fire, not iceberg, experts claim

The drilling rig business of Dolphin Drilling was restructured in late June, allowing those operations to continue under a new holding company incorporated in Jersey.