Glasgow’s low emission zone (LEZ) was illegal and unnecessary as air quality targets in most of the city had already been met, a court heard.

A lawyer representing garage owner William Paton told a judicial review that the local authority failed to follow established legal tests before making its decision to introduce the LEZ, which covers Glasgow city centre.

Lawyers for Glasgow City Council and the Scottish government are contesting the action being pursued in the Court of Session.

The second phase of the scheme – which started operating in June – aims to improve air quality by limiting which vehicles can enter the area.

Cars, lorries and other forms of transportation which do not meet emission guidelines are not allowed, and drivers who break the regulations can be fined.

Last month Mr Paton, the director of Patons Accident Repair Centre in Townhead, was given the go ahead to continue his fight against the LEZ after he said it would have a detrimental impact on his business.

He previously said he had commissioned a report by the Hilson Moran Institute to study the impact of the first phase of the LEZ for buses in the city centre which came into force in 2018.

Advocate Lord Davidson KC told the Court that the local authority failed to follow established legal tests before making its decision to introduce the LEZ, which covers Glasgow city centre.

He said that there were 27 monitoring stations in the city centre which monitor levels of Nitrogen dioxide (NO2) in the air – the gas which the local authority hopes to reduce.

He told the hearing that 25 out of 27 of the stations had recorded “downwards trends” of NO2 in recent years.

He said: “The submission is that the Low Emission Zone scheme is illegal as air quality objectives have been met already and they were continuing to be met by the time the Low Emission Zone was brought into operation in the city centre.

“To bring the scheme into being was an irrational decision by the council.”

Lord Davidson said imposing fines of hundreds of pounds for repeatedly breaching the LEZ was a measure as “draconian”.

Glasgow City Council’s advocate Ruth Crawford KC told judge Lady Poole that the local authority had acquired evidence about NO2 emissions which gave it a lawful justification to set up a LEZ.

Ms Crawford said the council had regard to different and more extensive types of data which showed that NO2 emissions were a continuing issue in the city centre.

She said this “modelling” gave the council a lawful basis to set up a LEZ.

Ms Crawford added: “In my submission that modelling cannot be properly criticised by the petitioner. It cannot be said by any stretch that the decision is irrational.”

The hearing is expected to conclude on Wednesday.