Arsonists destroyed a family car when it was left near a park overnight after being clamped by the DVLA, who thought it was untaxed.
Its owners claimed the £6,000 Vauxhall Zafira should not have been clamped, because it did have a tax disc.
Martin and Caroline George, from Bristol, parked their car near Durdham Downs in the city on Wednesday.
They said they had to leave it there overnight when DVLA officials refused to accept it was taxed and unclamp it.
It was set on fire during the night and when Mr and Mrs George, from the Lawrence Weston area of Bristol, arrived the next morning they found only a charred outline of where their car had been.
The DVLA said the case was being investigated.
Mr George, 24, said: “It's a real nightmare. The car was taxed until the end of October, but they clamped it anyway. “We rang up the DVLA but they refused to release it and it was left overnight near the park. We paid for the tax disc in May and have a receipt to prove it. There's no question it could have fallen down from the windscreen, it was securely in place. We even took a photo on our mobile phone of the disc after it was clamped”.
“We're gutted. We've got no car and we don't know if the insurance will pay out on it.”
The couple found just the charred outline of where the car had been because the burnt-out shell of the Vauxhall had been removed by the city council after firefighters were called out to tackle the blaze at 0100 BST on Thursday morning.
A DVLA spokesman said: “DVLA is sorry to hear of the vehicle keeper's distress.
“The Agency cannot comment on a specific case with a third party. However, I can confirm that the case is being investigated and DVLA will be contacting the keeper direct on this matter.”