How does the new London T-Charge apply to foreign vehicles?

Question

This year the Mayor of London has announced that a new emissions surcharge will apply to all vehicles that fail to meet certain standards:

From 23 October 2017, cars, vans, minibuses, buses, coaches and heavy goods vehicles (HGVs) in central London will need to meet minimum exhaust emission standards, or pay a daily £10 Emissions Surcharge (also known as the Toxicity Charge, or T-Charge). This will be in addition to the Congestion Charge.

However assuming I will drive my own foreign vehicle into London it is unclear how the system will work. Assuming my car does fit the right Euro standard, how am I supposed to prove this to UK authorities? Is there a sticker one should buy like in the German Umweltzones?

I presume UK vehicles are in a central database so the government knows their ecological footprint based on their license plate number. But the TfL website doesn't mention how it would work for foreigners.

Answer 1

Apparently it's currently unclear. There is a tool on the TfL website to check if your car is liable for the T-Charge, but it returns a strange response for foreign vehicles:

I presume that TfL considers all foreign vehicles exempt by default and only starts charging them if their registration for the London Low Emission Zone shows they're also liable for the T-Charge.