A man staged two bizarre explosions on a council estate in a vendetta against a shopkeeper, a court heard.

Jurors were told Mark Marchant placed an inflatable mattress filled with inflammable gas over a fence and ignited it.

The blast, captured on CCTV cameras, echoed around Weeds Wood in Chatham and dislodged ornaments from at least one resident's wall.

Paul Valder, prosecuting, said Marchant, 27, "caused the explosion, rather bizarrely, by setting fire to some sort of bed or inflatable mattress, which was full of inflammable gas".

Now Marchant, of Pimpernel Way, Chatham, could be facing an indeterminate sentence for public protection.

He denied causing an explosion likely to endanger life or damage property but was convicted.

Judge Andrew Patience QC said after the verdict: "This is a grave offence. I want to investigate whether it is necessary to protect the public from this man."

Yusuf Boztepe, owner of Walderslade Mini Market, in Yarrow Road, had experienced problems with local youths since opening in 2007.

When he complained to police, threats were made.

Mr Valder said Dean Goodearl made a number of visits to Mr Boztepe's shop asking him to drop the case.

On July 29 last year, Mr Boztepe was outside smoking when he noticed a group of people on the corner with the junction of Pimpernel Way.

Mr Valder said Mr Boztepe saw Marchant carrying something and then placing it by a fence next to the site of the demolished Woodman pub, before running away with Chris Young.

"It would appear they knew what was about to happen," said the prosecutor.

"Mr Boztepe describes seeing an explosion and flames within it.

"Afterwards, he was outside with his partner when a youth came up and said something to the effect that the people over there would do the same to his shop."

The group he indicated included Marchant, Chris Young, Dean Goodearl, 22, and his father Terry, 46.

"Mr Boztepe described Terry Goodearl pointing to the explosion and the direction of his shop.

"He took that as some sort of threat. He called the police."

CCTV, he said, showed Marchant place the mattress over the fence and 10 minutes later crouch down by it.

There were flames and smoke. Seconds earlier, a car had driven by.

The film was viewed by a bomb disposal expert and the scene was examined by a forensic scientist.