A train company has admitted its heating systems are “unacceptable” after passengers travelled in near freezing temperatures.

First Capital Connect (FCC) said it turned the heating off inside its carriages earlier than normal this year after a mild March but after a recent cold snap passengers said they could see their breath and were forced to wear extra layers to keep warm.

Richard Marris, who gets the 5.14am train from Preston Park, said an app on his phone showed the temperature on the train last week was just 2C.

He said: “It is uncomfortable. It is OK if you are walking to the station in that weather but you wouldn’t want to sit on a park bench.”

In a letter to FCC managing director Neal Lawson the 45-year-old wrote: “It may aid your empathy if you get into work early in the next few days, switch your heating off, open the windows then sit and work with a hat, scarf and gloves on.

"Unless you can see your breath you won’t be truly recreating what I experienced this morning.”

The Rail, Maritime and Transport Workers Union also criticised the lack of heating on trains.

FCC said it always switches the heating off in early April, regardless of the temperatures, and back on again in November but admitted issues with the heating systems on its class 319 trains in the past.

Last year there was a “major overhaul” of heating systems on the trains after the heating elements expired but were no longer being manufactured.

However this winter the new systems – with replaced wiring and elements – also cut out.

A company spokesman said the heating was on for sustained periods of time, which caused a protection circuit to trip out, switching the heating off.

He said: “In order to get the heating switched on again the train needed to be manually re-set inside a depot because the heating circuits are located underneath the carriages.

"We are looking at further modifications that can be made to avoid this in the future.”

The company admitted that passengers have had to endure cold temperatures on their train journeys.

The spokesman said: “Unfortunately the weather got very cold again towards the end of March, which meant that customers experienced some very cold journeys due to the heating being switched off.

"The engineering team are looking at the wiring diagrams for the heating circuits to assess if improvements can be made, as the current situation is clearly unacceptable.”