Kelly-Anne Hone, aged 28, was killed in October last year when her car collided with a lorry near her home in Cogenhoe. Her four-year-old son, Keelan, was airlifted to hospital in Coventry and survived.

The youngster visited Barclaycard's headquarters in Brackmills, Northampton, where 15 helmets were donated by the credit card firm for air ambulance paramedics, doctors and crew.

Mrs Hone's 20-year-old brother, Daniel Machardie, who works for the company's quality assurance team, said the charity was particularly important to him.

"I'm one of the people who has been directly affected by the work the Warwickshire and Northamptonshire Air Ambulance does," he said.

"The air ambulance came to the scene of the accident in which my sister was killed and took my nephew to hospital. Since then the charity has been very close to my heart."

WNAA chief executive, Andy Williamson, was presented with the 15 helmets, worth a total of £22,500, before an air ambulance helicopter conducted a ceremonial flypast in the skies above Barclaycard HQ.

Sheila Munroe, Barclaycard's UK chief executive, said: "The air ambulance is a favourite charity of Barclaycard and we have supported it for a long time.

"Last year we were particularly touched by the work the charity does when one of our colleagues was involved in an accident along with her son.

"Since then we have renewed our fundraising efforts."

Mr Williamson thanked the company for its vital contribution to the charity, which costs an annual £1.5m to operate.

He said: "Our old helmets had to be replaced and had it not been for Barclaycard, we would have had to try to find the money from somewhere else, which would have been a struggle."

Mr Machardie, together with friends Jason Bromwell, Russell Draper and Rob Harris, is preparing to cycle from London to Paris in memory of his sister later this year.

He hopes to raise £6,000 for the air ambulance following the four-day, 300-mile ride in September.

To sponsor the team, visit www.justgiving.com/08london2paris.