The infrastructure minister insists the plan to roll- out 20mph residential zones across the island is not a done deal.

But why then has the Department of Infrastructure installed poles for 20mph signs at a number of locations in Douglas already - even while a six-week period of consultation is under way?

The project to introduce 20mph speed limits in residential streets is expected to cost £400,000 - and has prompted concerns that it will effectively be a blanket speed limit across much of the island.

Maps produced by the DoI show the vast majority of roads in Douglas and Onchan will by covered by a 20mph limit.

But Infrastructure Minister Dr Michelle Haywood told the court: ‘This is not a blanket all-island 20mph scheme, this is not a blanket scheme. It is a residential areas scheme in line with the wishes of Tynwald.

She said the draft order for the island had been published but not yet signed or come into force. ‘This is not a done deal,’ she insisted.

But in recent weeks, poles suspected to be for the new 20mph signs have gone up at Ballanard Road and junctions along Johnny Watterson Lane - one of the few roads not to be covered by the new speed limit and close to the 20mph Home Zone already in place.

Chief Constable Russ Foster has said there was no evidence that reducing the speed limit on 30mph roads will have any impact on the number of people killed or seriously injured - and he would ‘not be supportive of the DoI imposing 20mph speed limits on residential roads per se, except for where there are particular hazards such as the area of a school’.

The scheme dates back to July 2020 when Tynwald members overwhelmingly supported an amendment by Douglas Central MHK Ann Corlett that roads in residential areas and by schools should be 20mph by defaults.

Last month, Tynwald approved the implementation plan with enhanced community engagement and consultation.

Dr Haywood insisted no changes have taken legal effect and final decisions will be made only after local engagement is concluded.

She told Tynwald that under the implementation plan there would be a six-week consultation in Douglas and Onchan with signs installed over the summer.

Consultation for the northern areas would take place over the summer and signs expected to be installed in the autumn while in the central corridor there would be consultation during the autumn and signs anticipated to be installed next spring.

Finally, the southern area would be consulted in winter and signs set to be erected in the summer of next year.

The Minister insisted that a thorough assessment had been carried out to determine the suitability of roads for 20mph limits

Rob Callister has described the situation as a ‘political train crash’.

He told Tynwald: ‘At no point did this court ask the DoI Minister and her department to roll out 20mph zones right across Douglas and Onchan and then across other constituencies over the next 18 months and all without any form of engagement or consultation.’