A hi-tech York firm supplied the electronic clocking-in devices which sparked wildcat walkouts by British Airways check-in staff and the stranding of thousands of passengers at Heathrow Airport, it was revealed today.

Mitrefinch, on the Green Lane Trading estate, was today standing by its product, the award-winning TMS system.

The walkouts were prompted by the fear that the electronic swipe system of clocking on - automatic time recording - would be used to impose annualised hours so that staff would be sent home in quiet periods, but have to make it up in periods of demand. Amid the chaos of angry BA passengers at Heathrow unable to get flights, the fear has been denied by BA bosses. Today Mitrefinch was refusing to comment on the strikers' claims, referring all such questions to the airline.

Debbie Guppy, Mitrefinch's director of business management, said: "We provide the system to about 2,500 clients in the UK, Ireland, France and Australia and British Airways is one of our valued customers.

"If there are any negative vibes as a result of the strike it is not down to our system.

"The facility to manage time in this way exists, but it would need a management decision. It is not an automatic feature and it could be achieved equally as effectively with a paper-based system.

"The advantage of having a computerised time and attendance system means being able to plan better, safer and with greater efficiency. It is able to cut down financial administration by automatically calculating time worked and wages paid."

Ms Guppy said the system was actually helpful to staff. "They can access it themselves, to book holidays and view their working times."

Updated: 10:46 Friday, July 25, 2003