While visitor numbers soar, workers are paid below the living wage in employment practices recalling the navy in the 19th century

Braving the high seas and undertaking physically demanding work, the crew of the Cutty Sark might have expected pay to match. Instead, by 1882 the men who sailed what was once Britain’s fastest ship earned just one pound and eight shillings (£1.40) a month – less than agricultural labourers of the time.

More than a century later the custodians of Britain’s naval heritage are at the centre of a struggle over pay and working conditions at the vessel’s final resting place. In Britain’s first industrial action of 2018, some of the lowest-paid employees of the Royal Museums Greenwich will go on strike on Monday to protest against changes to their hours, meaning longer shifts and shorter breaks for the same wage.

A Unesco world heritage site and one of the UK’s top 10 visitor attractions, the museum in south-east London buzzed as usual this weekend to the footfall of hundreds of tourists from home and abroad.

Some 17 million visitors a year now come to the site, which includes the National Maritime Museum, Royal Observatory and a villa known as the Queen’s House. Visitor numbers have more than doubled since the ship underwent a £50m restoration several years ago after being ravaged by a fire.

On Monday morning picket lines will be in place at the main entrances on the Royal Museums site. “It’s getting increasingly busy here, whether that’s due to the fall in the value of the pound or down to advertising Greenwich,” said Tristram Spencer, one of up to 60 union members from the front-of-house staff who are expected to take part in the strike.

“That’s something that is felt by staff, who are essentially always in the frontline. We are not allowed to sit down, for example, while other galleries have a chair. Then there are colleagues with all kinds of medical conditions who are standing up on hard surfaces or being kept to a single rotation in the one place day in, day out.”

In terms of pay, the majority out of around 100 front-of-house staff earn £7.50 an hour (the “national living wage”). “It’s one of the largest things for us, and why people are so upset,” said Spencer. “We are still one of the only London museums where people are not getting the London living wage of £10.20 per hour. Some people can only afford one meal a day.”

“When you recall what those on board the Cutty Sark might have earned, then it sort of puts things in perspective. I think people can see how far we have come – or not.”

The row stems from contractual changes which visitor and sales assistants say were imposed on them in November. Breaks were reduced by 40 minutes, the working day now runs from 8am-8pm, according to the workers’ union, Prospect. The union adds that for those on the lowest pay, removal of paid breaks means they will effectively lose out when the national living wage increases in April.

While staff from the Cutty Sark and other departments at the museum will not be on strike, they are being asked to show support in whatever way they can with their colleagues from the other sites across the road owned by Royal Museums. The picket is not designed to stop members of the public from entering the museum.

Kevin Fewster, director of the Royal Museums Greenwich (RMG), said that “harmonised” terms and conditions had been introduced in November for front-of-house staff due to a merger of the museum’s visitor experience and commerce departments.

“One of the many proposals on the table was to cease the payment for a rest break, which is in line with most colleague institutions across the sector and includes maintaining annual salaries at existing levels.

“This increases hourly rates of pay, and proves an immediate benefit to some part-time staff and those working overtime,” he added.

“After consultation, the majority of the RMG front-of-house team have agreed to the new terms and conditions. A reduction of breaks for some of the staff involved has remained at issue, and after a year, of negotiations with the union, discussions have ceased without full agreement being achieved, so the decision was taken to impose the new terms and conditions for those staff who had not yet agreed them.”