Farmers on Salisbury Plain, near Devizes, have been astonished over the last few weeks to see what looks like an old-fashioned red phone box jogging along farm tracks.

In fact, it is Sid Keyte, 43, training to run the London Marathon attached to the 15kg contraption, about as heavy as a Labrador dog, raising money for the mental health charity Mind.

Father-of-three Mr Keyte, who works for Systems Engineering and Assessment near Bath, has run the marathon three times before, with a best finishing time of three hours and 35 minutes, but this time he wanted to make an impression on potential sponsors.

He said: “Everyone has seen the rhinos, camels and other amazing constructions so I wanted to do something like that.

"I was thinking about what I could do and just happened to be driving past a phone box when it occurred to me I could make a lightweight version, light enough to wear for 26.2 miles.”

Mr Keyte built himself a frame to fit over his body and bought four cardboard phone box panels from a theatrical suppliers.

He said: “They had to be light but also as rigid as possible. I think I’ve got it right.

“I’ve been out running, keeping to farm tracks away from main roads to avoid people seeing me as much as possible, but one farmer did stop me and asked if I was all right.

“With a 15kg weight around me I don’t expect to finish in much under seven hours but hopefully it will attract more sponsorship for Mind.

“I chose the charity because I know a number of people with mental health problems. One in four people nationally suffer in this way and my run is as much about raising the profile of the disease as it is about raising money.

“Mental illness still carries a huge stigma and we ought to accept it as a medical condition as normal as a broken leg.”

Anyone who would like to sponsor Mr Keyte can visit