Southampton’s most well known cycling campaigner is fighting for her life following a freak accident while out riding her bike.

Lindsi Bluemel, chairman of Southampton Cycling Campaign, suffered life-threatening head injuries after coming off her bike in the cycle lane of a busy dual carriageway yesterday morning.

Just two days ago the 56- year-old had her helmet stolen and police confirmed she was not wearing one when the accident happened as she attempted to ride over a five-metre long piece of plastic which was lying diagonally in her path.

Officers were forced to close the busy Wessex Way in Bournemouth just after 9.15am yesterday while they examined the scene of the crash.

A spokesman for Dorset police said that eyewitnesses reported how Mrs Bluemel’s bike suddenly wobbled and the back wheel slid, causing her to fall.

Passers by stopped to give first aid before she was taken to Poole Hospital by paramedics.

Doctors last night said she was in a critical but stable condition.

Mrs Bleumel has been a forthright campaigner in Southampton, arguing for better cycle routes and facilities.

She has also been heavily involved in organising various events to encourage more people to get on their bike.

One of the most notable was Southampton Skyride, which took place in August, which she took part in.

Mrs Bleumel’s most recent campaign was called Missing Links, where she argued for low-cost improvements to cycle lanes so they would be joined up through the city.

The keen cyclist has also spoken regularly on the rights of cyclists, green issues and organised many of Southampton’s events during National Bike Week in June.