A woman who pulled over as her daughter suffered a hypoglycaemic seizure has been fined £690 by Merton Council for parking illegally.

Susanne Bayly of Coombe Lane, Raynes Park, stopped outside Tesco on Merton Road in January last year after her daughter Lesley, 14, started to have a fit caused by a rare diabetic condition, hypo insulism. Just moments later a traffic warden issued a ticket and when Ms Bayly attempted to appeal the fine, Merton's traffic services sarcastically asked her to prove her daughter was dying.

"It's the whole way that we've been treated that really gets to us," said Ms Bayly.

"We've been made to feel like criminals even though we've tried to appeal for entirely genuine reasons.

"There's a ridiculous flaw in the system that when a child suffering from a serious medical condition doesn't qualify for a successful appeal."

The fine has grown after two unsuccessful appeals and eventually Ms Bayly was forced to back down when, two weeks ago, parking officers clamped her car without notice.

She has now paid the fine but only with financial help from a friend and is at a loss as to why her appeals have not been upheld - Merton Council had previously cancelled a ticket given under similar circumstances. And in 2006, Westminster Council removed a wheel clamp within 40 minutes after Ms Bayly was forced to abandon her car to seek medical treatment.

Her daughter's condition means that she is regularly prone to hypoglycaemic episodes requiring immediate attention, but this does not qualify Ms Bayly for a blue badge.

Twickenham MP Vince Cable is campaigning for the law to change after a consultation on the "blue badge" parking scheme for the disabled.

He said: "I fully appreciate that it is important to prevent a devaluation of the scheme with councils handing out blue badges indiscriminately. But there is at present a degree of rigidity which prevents really needy cases receiving help."

A Merton Council spokesman said: "Merton Council does not tolerate illegal parking. Where there are special circumstances the council will give consideration to all representations received against the issue of Penalty Charge Notices.

"Ms Bayly was issued PCNs for parking in contravention of the parking regulations. This happened on two occasions and, including the bailiffs costs, the charges amount to £329.34 for each offence.

"Ms Bayly has not provided any proof of emergency and she did not appeal to the Parking and Traffic Appeals Service for an independent adjudicator to hear her cases, as is her right."