A London businessman has accused Norwich Union of putting his son's life at risk through shoddy car repairs.

Tim Siney, managing director of Wheelers Print in Islington, says his company's £15,000 Japanese Subaru import was so badly botched by NU's approved repairer, Nationwide in Friern Barnet, that his son Jake, the vehicle's regular driver, could have been killed.

When Siney took the vehicle to another garage for a respray, he says the bodyshop claimed the vehicle was dangerous and NU had to be called to get the shoddy work redone. NU admits problems with the car repairs and that the claim was mishandled, but it denies the car was dangerous.

"We took it to NU's recommended repairer and they took four months to carry out the repairs," says Siney. "When we finally got it back we drove it to another garage, who told us it was a botched job."

Siney has written to NU, but says he has received no apology. He claims an NU engineer confirmed verbally that the repairs were dodgy and the insurer took the vehicle back to Nationwide. It was released with the repairs done properly four days later.

Jake Siney, 25, said: "The chassis hadn't been straightened. The car didn't drive properly and it kept darting across the road. The front bumper wasn't bolted on and the bonnet flapped in the wind."

Nationwide said: "We do not discuss individual cases with the press.." But it added it would contact Siney direct.

NU admitted problems with the bumper, tyre wear on one side and a problem with the suspension geometry, but was unable to give details.

Jake Siney also claimed that NU had demanded back the replacement car provided while the Subaru was in the garage, because the original repair had taken too long. NU claims it did so after hearing reports of it being driven recklessly in a supermarket car park, as confirmed by Jake's father. It also admitted its failure to respond to Siney's letters. "We do need to do something about that," it said.

But NU insists the car had suffered damage from a previous unreported accident, which caused the problems.

In a prepared statement, NU said: "We are concerned at the length of time taken to resolve this matter for Mr Siney and we are investigating it further. This is a complex matter, which appears to involve more than one accident and has been made even more complicated by the fact that the car was a grey import. We have passed the file to our claims director, Simon Machell, for immediate review and undertake to contact Mr Siney by the end of this week.