Fears have been raised that motorists could be forced to pay to cross the Tyne.

The Tyne Bridge has one of the worst levels of air pollution in the North East, and a so-called toxin tax could be levelled in a last-ditch bid to tackle the problem.

While councils are being urged to develop plans to avoid the need for charges, Gateshead Council has questioned Government figures on pollution at the crossing.

But if Newcastle and Gateshead councils were forced to introduce a charge, how might it work?

Here, we look at similar systems used across the country and how they might apply here.

How much do tolls generally cost?

Many North East motorists will be familiar with the system at the Tyne Tunnels, which connect Jarrow and Wallsend.

Here, motorists pay £1.70 to travel under the Tyne, with a higher cost of £3.30 for larger vehicles. Similarly, at the Mersey Tunnels, in Liverpool, there’s a £1.70 charge.

For many toll bridges across the country, costs are similar.

At the Humber Bridge in Hull, it’s £1.50 per crossing for ordinary car or van drivers.

To cross the Tamar Bridge between Cornwall and Devon, motorists pay £1.30, or £3 with a trailer.

At both of these bridges HGVs and lorries over 3.5 tonnes pay more, depending on the size of their vehicle and how many axles it has.

The smaller Dunham Bridge, in Lincolnshire, it costs just 40p to cross with a four-wheeled vehicle.

More expensive is the Severn Bridge and the Second Severn Crossing, which run between England and Wales. There a driver of anything from a standard-sized car up to a minibus will pay £6.70.

How do they work?

Early morning rush hour traffic on the Tyne Bridge, Newcastle
Early morning rush hour traffic on the Tyne Bridge, Newcastle

At these sites, you pay per crossing, in toll booths placed at the start of the bridge or road.

In many of these places, including the Tyne Tunnels, you can pay for a number of trips in advance at a discounted cost.

However, there are a number of reasons why a Tyne Bridge toll would work rather differently.

A toll designed to reduce air pollution (as opposed to fund the construction and maintenance of the road or bridge) would most likely mean different vehicles would incur different costs, depending on how much pollution they produce. So it wouldn’t simply be a case of throwing a set charge in the basket.

And from a purely practical perspective, we’d be unlikely to see toll booths at either side of such short bridges.

So would it be more like a congestion charge?

If it were introduced, the so-called ‘toxin tax’ would probably look a bit more like the congestion charges seen in London than a conventional toll.

This is paid either in advance, on the day of travel, or the following day, online or over the phone.

In London, motorists can also set up automatic payments, so their account is charged whenever they enter the congestion zone.

Again, because it’s designed to reduce emissions, the cost would vary depending on the sort of vehicle being driven.

What about a Clean Air Zone - what’s that and could we have one?

Newcastle City Councillor and Liberal Democrat opposition transport spokesman Greg Stone said the region had avoided being one of the five UK cities forced to introduce a Clean Air Zone ‘by a whisker’.

So what is a Clean Air Zone and if we did end up with one how would it work?

They are being introduced in Leeds, Birmingham, Nottingham, Derby and Southampton. In these zones, various measures, including charges on drivers, can be taken to try and improve air quality.

Some vehicles will be hit with charges for entering while others will get away without a charge, depending on how much they pollute.

Electric cars, for instance, might be free, with scaled charges depending on how much your vehicle affects air quality.

It’s likely that diesel vehicles would be expensive under such a system.

There could also be total bans for certain kinds of vehicles, or bans for certain kinds of vehicles at particularly busy times of day.