Let me tell you about a huge piece of prime Central London real estate. It’s bigger than Hyde Park, yet it’s undeveloped. In fact, 150 years ago Londoners were making more use of it than they are now.

It enjoys some of the best views in London and borders some of the most iconic landmarks. It could create all sorts of possibilities for people, not least billions of pounds worth of business, as well as alleviate London’s congestion and housing problems.

I bet you think I’m living in cloud cuckoo land. No such thing exists.

Except that it does.

I’m talking about the River Thames.

The Thames is going to waste

The Thames is a huge resource right on Londoners’ doorsteps, and it is barely being used. A few party, pleasure and tour boats; some boats carrying freight; HMS Belfast; the Thames Clippers; a couple of floating restaurant-bars; and the occasional mooring for houseboats.

That’s pretty much it.

Plenty of office and apartment blocks have been built along each side (what a missed opportunity to produce something beautiful that was), but in front of them, from Chiswick to the Isle of Dogs, mile upon mile of unused bank wall, foreshore and river with hardly any activity. It’s an economic desert.

Look at some images of the Thames in the 19th century and you’ll see a haven of activity. Boats ferrying people about and delivering goods. Industry, commerce – as well as people living in boats moored all along the banks. It was bustling. Now there’s practically nothing.

“Why so?” I asked the Port Of London Authority (PLA), the body charged with the management of the Thames. Its very helpful spokesman vehemently denied my charges. “So much is happening”, he said. He pointed to the new Thames Clippers as evidence, as well as the fact that much of the equipment and materials for the new station at Blackfriars was brought in by boat. “It’s the UK’s busiest inland waterway, both for freight and passengers”, he said.

But so it should be. It’s the longest river entirely in England and it runs through the capital. Yet the other day, I went for lunch in The Gun, a famous river pub on the Isle Of Dogs. In the hour I was there, I counted four boats go past. The bank wall is unused on either side. There is not a lot going on.

I can easily imagine a Thames that instead is a haven of activity, with beautiful floating buildings, homes, shops, workplaces, offices, cinemas, theatres, and small craft ferrying people in between. Maybe there are walkways.

The possibilities are enormous. Of course there are ecological and aesthetic concerns, but these can be addressed. Take a leaf out of Venice’s book.

What’s stopping the development of the Thames

One major issue standing in the way of floating structures, as my friend from the PLA pointed out, is the tide. But this is something that can be overcome by entrepreneurs, engineers and innovators. Heck, they dealt with the tide in the 19th century. We are over a century more advanced.

I have spoken to skippers and numerous river folk who live on some of the few moorings left along the Thames. They all shake their heads wearily when the subject of lack of development is brought up. It’s a conversation they’ve had a million times, one that frustrates and baffles.

What would you do if you were in charge of the Thames I ask? Several of them say the first thing they would do is get rid of the PLA. Its regulations and demands create barriers to activity.

The next problem is the issue of ownership.

On the non-tidal Thames there are riparian rights. The owner of the bank has ownership of the bed to the middle of the river. On the tidal Thames however – which stretches as far as Teddington Lock – these riparian rights are less clear.

The PLA inherited ownership of the riverbed and the foreshore from the City of London in the early 20th century. The bank and one boat width immediately next to it is said to owned by somebody else. Often there is a dispute over ownership of the wall alongside the river. Ownership of the flowing water is even less clear.

Moored boats, complain those who live in the river, even if lived on for many years, have fewer rights than squatters. They can be moved on with little notice or permission.

Reed Wharf by Tower Bridge, Nine Elms in Vauxhall, St Mary’s Church and the Cooper Gallery in Battersea, these are all moorings that have been there for decades. Yet they are all constantly in and out of legal disputes over ownership.

When ownership is unclear, little capital gets invested. Things fall into disrepair. Take a look at the mooring by St Mary’s Church in Battersea if you want to see the depths of disrepair to which boats on an unmaintained mooring can sink.

This gives rise to ‘nimby’-ism. Riverside properties don’t want their view of the river spoiled by grotty old boats. It’s all led to this chronic lack of use.

If Boris Johnson wants to get people using the river – and he’s said he does – he can’t just say ‘Everyone in a boat!’. Boats are famously depreciating assets. People will not use the river unless they stand to gain by it in some way.

How ironic that a land value tax (LVT) should be the answer to these water problems.

The central third or so of the river should be set aside for traffic. On the lateral thirds, the foreshore and the bank a simple tax should be levied. This tax would be a proportion of the potential annual rental value of that plot.

The obligation to pay tax will force many owners, including the PLA, either to make use of the plot – to develop it in some way (an ecologically and aesthetically agreeable way, of course) – or to sell it someone who will.

The obligation to pay tax will quickly clear up the issues surrounding ownership. If you own, pay tax on it. If you don’t, shut up.

Then the river can thrive again in the true tradition of London. Magnificent floating edifices can be built, homes, places of work and entertainment, river commerce can flourish once again, congestion on our roads can be eased.

What’s more, fantastic communities can flourish – boating communities are as close-knit and happy as you get. Talk to anyone who’s lived in one if you need evidence of this.

A simple tax could generate some truly ground-breaking, innovative and world-leading development. The Thames is a huge opportunity. It’s what made London. Why are we not making more use of it?