Warminster millionairess Bella Hopewell, managing partner of private bank C Hoare and Co, is embroiled in a legal battle over a tragedy that left her husband dead and son critically hurt.

Richard “Boris” Hopewell died from his injuries when he collided head-on with an ammunition lorry. Son Tom, then 10, was badly injured.

Tom was airlifted to hospital with two broken legs and internal injuries. He needed numerous operations following the crash in March 2008.

Mrs Hopewell, of Gasper Cottage, Gasper, Warmin-ster, is suing her husband’s estate for damages of £150,000 on behalf of her son, Tom.

Law firm Halliwells wrote, admitting the late driver’s liability, in December 2009, according to a writ issued at London’s High Court.

The two sides are thought to have been unable to agree the level of compensation.

Court papers appear to blame Boris Hopewell for the crash on the A303 near Mere, on the Somerset border.

The writ states: “For reasons unknown, the defendant drove the vehicle on to the wrong side of the road and into the path of oncoming traffic.”

At Mr Hopewell’s funeral, donations were invited for Ataxia UK, which supports people with a neurological disorder that affects balance and coordination.

Mrs Hopewell is the daughter of Henry Hoare, whose ancestor, Henry Hoare “the Magnificent”, founded the private bank C Hoare and Co.

She became a managing partner of the bank in 2001, after working at Cazenove, where she met her husband.

In 2010, Mrs Hopewell opened a community pavilion and football facilities, named after her husband, at Zeals in south west Wiltshire.

Tom, a talented saxophone player, is said to have made a fantastic recovery.

At the time of the accident, the writ says, Mr Hopewell negligently drove too fast and crashed into a lorry carrying ammunition for the Navy.

He allegedly moved without warning or regard for traffic, when it was unsafe and failed to keep a proper lookout or warn of his approach.