Midsomer Norton is expected to be minus five overnight on Wednesday - the coldest temperature of the winter so far.

It is forecast to be minus four the following night, before warming up at the weekend.

So it is timely that National Highways have put out a reminder to give their gritters space as they tackle the main motorways.

Five National Highways gritters were struck by other vehicles while they were out and about spreading salt last winter. 

 It compares to just one incident the year before and left each of the vehicles with visible damage. 

Now motorists are being urged to give the gritters time and space to do their jobs as National Highways continues to treat roads this winter season, with snow forecast early this week in northern areas of the country. 

Darren Clark, Severe Weather Resilience Manager, at National Highways, said: "It is quite shocking that five of our gritter vehicles were struck while in the course of their duties last winter season. 

"With the current winter conditions it is a timely reminder for drivers to give our vehicles the time and space they need to do their jobs to keep everyone safe. 

 "We also encourage everyone to follow our TRIP messaging so they are fully prepared for their journeys." 

 National Highways also reminds motorists to keep TRIP in mind ahead of journeys – Top-up: oil, water, screen wash; Rest: rest every two hours; Inspect: Inspect tyres and lights and Prepare: check your route and the weather forecast.   

How many gritters ?

National Highways has 443 state-of-the-art Romaquip-Volvo gritting vehicles and a total pool of around 530 gritting vehicles This also equates to one gritter for every eight miles of road. 

The company started the winter season with around 280,000 tonnes of salt at its 128 depots. 

Mr Clark added: "If you are going to pass us, please do so courteously, pass us safely and legally, or even better, if you are able to stay back, you will actually help the salt on the road activate even more quickly by crushing and breaking it into the road surface which benefits everyone. 

"It's worth remembering too, we are not gritting all the time. Some of our fleet may come off at particular junctions or return to depots while other vehicles take over, lowering any inconvenience to motorists. We are once again totally committed to working around the clock on these seasonal operations to keep all road users safe and thank everyone in advance for their patience and understanding." 

Ready for winter season  

Along with more than 250 weather stations National Highways works with independent meteorological experts Metdesk which run from October 1 to April 30 and complement the national Met Office weather forecast, providing a level of granularity and precision about changing road surface temperatures across the road network.

Abigail Oakes, Senior Account Manager at the Met Office, said: "We are delighted to continue our close working relationship with National Highways this winter season.  

"Our staff, be that meteorologists embedded alongside the National Highways team in Birmingham during the winter, or Met Office staff working from Exeter to deliver and support throughout the year, are proud to continue this partnership, which allows for the best possible support for road users during periods of severe weather."