Cost escalation infrastructure social value Tourism

The Cost of the Marble Arch Mound

The Marble Arch Hill, a temporary tourist attraction divided opinion, tripled in cost, and resulted in heads rolling.

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Let’s look at what has been branded London’s worst site! The Marble Arch Hill (or Mound as it became known) was a temporary art installation/ tourist attraction in the centre of London, which, for 6 months divided opinion, tripled in cost, and resulted in heads rolling.

On the go? Why not listen to podcast episode where I discuss the article (click this link for the episode). You can listen on most platforms!

The Council Decides

If you were to go to Marble Arch in London now, next to it you would see the remnants of a strangely shaped, mini hill, green in places, with trees sticking out of it, you’d be forgiven for missing it. But this was the site of a hugely controversial temporary structure called the Marble Arch Mound, which closed it’s doors to the public recently.

So Westminster Council decided to commission this work, and taking a quote from the Council leader Rachael Robathan:

“We hope it will give people an opportunity to look afresh and with wonder at this well known, but sadly increasingly overlooked, area to recognise its beauty and importance. We want visitors to appreciate the wider context of this iconic location and its close connections to Oxford Street and Hyde Park, as well as other key destinations in the West End and beyond.”

At a time where, exacerbated by the pandemic lockdowns (there was a £7.4bn drop in spend from overseas visitors in London in 2020), the world famous Oxford Street was reeling from the increase in e-commerce. When the mound was announced, it formed part of the Council’s £150 million plan to regenerate Oxford Street.

Some of the lines at the time of the announcement should have given pause for thought. Early considerations about the project were exemplified by Mylondon who asked “will the Marble Arch viewing platform save London or just be a ‘bonkers’ waste of money?”

The Plan

From June until December 2021 the Mound was to expect around 2 to 3 thousand visitors a day (around 200,000 in total). Each would pay around £6.50 to have the opportunity to climb up to the viewing platform and see panoramic views of Hyde Park, Mayfair and Marylebone in a way no one had ever seen before. From the top of a mound… The ground floor inside the hill had space for events and exhibitions.

Concept for the Marble Arch Hill (courtesy of MVRDV)

Then in December, the scaffolding was designed to be reused, along with the wood, soil, grass and trees (all going to parks and gardens in the area). Oh, and there was a planned Marks & Spencer food court planned too. Early in the planning stage the budget was £900,000. The initial estimate for construction cost went up to £1.99m in February 2021.

Not In My Backyard!

Here are some quotes taken from various sources on the internet from some unhappy locals:

I don’t know how much it will cost but willing to bet it won’t come cheap!

It feels like an awful lot of money to spend on something that elaborate which is only temporary.

We are yet to find any local residents in the West End that like the idea.

What Actually Happened?

There was no fanfare, but the media reports at the time of opening painted quite the ugly picture. Unfinished, a pile of rubble and an average google rating of around 1. You can find pictures on the web showing patchy grass covered over wooden struts with little foliage. Visitors who pre-booked tickets were given refunds which were replaced with a free ticket to come back later to quote a Westminster Council statement, “see the Mound at its best”. The attraction was opened while it was still being constructed and was then temporarily shut after just one week.

The Fallout

There are lots of criteria to consider in what makes a bridge a green bridge.

The Deputy council leader quit and the council leader apologised after it was revealed that the project cost escalated to £6 million pounds! An internal review was launched and the Council leader was quoted as saying “The Mound opened too early, and we apologise for that. With regret, I have accepted the resignation of my deputy leader, who led the Mound project. The Mound may delight or divide views and that’s ok, but we’re confident that in the end it will fulfil its original brief.”

The cafe idea was scrapped. And things got worse.

The grass was greener on the other side (Image courtesy of MyLondon)

The Truth About the Estimate

An article in The Standard stated that the senior council leaders covered up warnings about the costs escalating, so far as to hide critical information from cabinet members and over estimated how much the mound would make in ticket sales. So the actual claim was that at £8 per ticket for an adult, and £20 for a family of four, there would be 280.000 paying customers. Additionally, there would be sponsorships that would then pay the difference. “In order to meet the cost expectation, set by the responsible cabinet member, the Review Team found evidence that the senior officers responsible for the project descoped and omitted critical elements of the Marble Arch Mound project. At the same time income estimates were revised upwards with no evidence provided to support these assumptions.”

What’s more damning are the suggestions that:

“despite clear and repeated warnings around the likely cost of undertaking such a project from experienced officers and the suppliers tasked with building the Mound, overly optimistic financial updates were given to senior leaders.”

It was revealed that the council did not robustly challenge the project costs against the business case, even though they have a team in-house called the Capital Review Group, whose function is to prioritise capital spend and do these challenges.


So, despite things going late and over budget, around 150,000 people did visit the Mound. It created attention, and people certainly visited the site, possibly due to its infamy. Did the costs escalate or were the assumptions completely wrong, and conciously biased? There are questiosn to be answered still on this project. Opening too early, promising too much. Was it an art installation, was it a tourist attraction? Was it designed as part of a wider plan to increase footfall in the area? Was the idea to completly transform the reason for visiting Oxford Street? I think it must have been a confusing business case, because I still don’t quite understand the fundamental purpose of the Marble Arch Hill. I think that’s where it went wrong for the project.

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