Farmers have condemned "idiots" who threw mock "Molotov cocktails" onto the edge of a tinder-dry field - just days after wildfires devastated Norfolk communities.

Tim Barrell and James Lake found three glass beer bottles, with tissue paper sticking out of the neck, on a roadside field margin between Shipdham and Dereham.

Although there was no sign of any fuel or obvious attempts to light the tissue, they said it could be a deliberate attempt to start a blaze - with discarded glass alone being enough to ignite dry vegetation.

It comes after last week's heatwave sparked almost 300 fires in a single day, destroying around 20 homes as well as cropped fields and nature habitats.

Mr Barrell, who farms at Shipdham, said: "It looked like a Molotov cocktail. They had stuffed tissue paper into the bottle and chucked them off a main road into a field.

"I cannot believe that there are people wanting these fires to happen, whether it is youngsters or idiots, I don't know.

"We are trying to do our jobs but our lives are being put at risk by these idiots."

Farm contractor Mr Lake added: "No wonder we have had such awful field fires when idiots are going round doing this.

"It is either people with tiny minds doing this for fun, or with malice. It beggars belief."

Although the farmers tweeted their discovery to Norfolk police, the constabulary said it had not been formally reported "and therefore we would not comment on it".

Fire safety officers said, even without any criminal intent, discarded glass bottles are still a combustion risk as they can focus the sun’s rays on dry vegetation.

Tony White, Norfolk Fire and Rescue Service’s head of prevention, said although the temperature had fallen from last week's record highs, the prolonged dry weather conditions meant the "risk of fire remains high".

“Everyone can do their bit by staying safe and being aware of the risk of wildfires," he said.

"In these conditions, leaving glass outside can be enough to catch the sun’s rays and start a fire, while driving on dry grass or fields – where your vehicle’s exhaust can reach temperatures over 500C – can be a risk as well."