I'm a fan of oversized structures open to the public with fantastic views across cities, from the Eiffel Tower to the Rockfeller Centre. I'm even a fan of Anish Kapoor's work. (Isn't it time the Queen created a new post of artist laureate specially for Kapoor?)

But the decision to embrace ArcelorMittal, the world's largest steelmaker, as the sponsor for the £19m Kapoor-designed Orbit tower – or Boris's Olympic folly as it is becoming known – is one that really sends me into a spin.

I don't care that the tower resembles a 115m helterskelter tangled in Wembley stadium's arch. But during London's bid for the Olympics, sustainability was the buzzword. The London games would "set an example for how sustainable events and urban planning take place around the world in future."

Is the Orbit the type of landmark the organisers of the 2012 Olympics – who have some impressive green achievements under their belt – really had in mind when it said London would host the world's "first sustainable Olympic and Paralympic Games"?

The commission was agreed by the London mayor, Boris Johnson, and the Olympic minister, Tessa Jowell. But the choice of ArcelorMittal appears to have been thanks to a chance encounter between Johnson and the steel magnate Lakshmi Mittal "in a Davos cloakroom".

But for Johnson to make his mark on London 2012 and its legacy with thousands of tonnes of steel, one of the world's most carbon-intensive materials, appears at odds with the sustainable values of the Olympic Delivery Authority and the London Organising Committee of the Olympic Games and Paralympic Games (LOCOG) – and the spirit of the times.

ArcelorMittal's court challenge to Europe's cap-and-trade scheme, recently reported by PointCarbon, is its most recent act of resistance against the EU emissions trading scheme (ETS), the main mechanism for driving down CO2 levels in industry. ArcelorMittal's action brought before the European general court sought damages for being forced to pay for its greenhouse gas emissions because the company claimed the scheme threatened its business unfairly. The court dismissed the challenge last month.

Although ArcelorMittal is cagey about its own figures for allocation of carbon credits, climate campaigners have been hard at work poring over data for the EU ETS. Sandbag which campaigns to restrict the number of credits traded on the ETS, last year published a report with the help of Carbon Market Data claiming that by 2012 the company would have 80m carbon credits that it does not need, and was given for free. If sold, the company stands to make £1bn in windfall profits, says Sandbag. A tidy profit for doing, well not much, made by a company led by Mittal, who also happens to be Europe's richest man.

But this prospect hasn't prevented the company – along with the rest of the industry – from whingeing about its obligations under the EU ETS and demanding special treatment from the European commission by warning of "carbon leakage", that they claim would force factories to relocate to regions which have no cap-and-trade scheme.

In its corporate responsibility report, How will we achieve safe sustainable steel, ArcelorMittal admits its emissions are high. Every year it produces around 220m tonnes of carbon w – equivalent to the whole output of the Czech Republic or just under half of the UK's total emissions in 2009.

ArcelorMittal aims to reduce emissions from steel manufacture by 8% in 10 years' time and is already the world's largest recycler of scrap steel – to the tune of 25m tonnes a year – which it claims saves 35m tonnes of CO2 annually. ArcelorMittal has already won one of the first gold medals of the games with this PR coup to sponsor the Orbit. But it has missed an added opportunity to extra shine to its steel business with a commitment to using at least a large proportion of recycled steel in its construction.

But when I asked ArcelorMittal and the mayor's office to explain what makes the steel giant an appropriate sponsor of the lasting monument to the "world's first sustainable Olympic games", both refused to comment directly.

They referred me to a press release by the London mayor's office in which the only mention of sustainability comes in the notes at the bottom:

ArcelorMittal recognises that it has a significant responsibility to tackle the global climate change challenge; it takes a leading role in the industry's efforts to develop breakthrough steelmaking technologies and is actively researching and developing steel-based technologies and solutions that contribute to combat climate change.

Bryony Worthington from Sandbag says: "Boris really should have done his homework. While on the surface ArcelorMittal like to appear a responsible company they have been very active opponents of climate change regulations in Europe. They have also been amassing a small fortune in spare CO2 emissions permits as a result of lobbying for generous allocations. They now have more control over emissions trading in Europe than some countries."

As a Londoner and a sports fan, I wish he'd bumped into someone else in the cloakroom at Davos. But who, one of the other sponsors such as British Airways or BP? Last year ArcelorMittal had revenues of $65.1bn (£42.4bn). What other company would have £16m spare right now? In these straitened times, would London be better off without such a monolith to a steel empire with CO2 emissions equivalent to that of the Czech Republic?