The 24-year-old equestrian champion said public transport is often inaccessible for disabled people and impossible to use.
The former Charters School pupil in Ascot is now backing a new campaign, A2B For All, alongside her hero Paralympian Tanni Gray-Thompson which aims to ensure public transport does not discriminate against disabilities.
Just a few months ago Sophie, who was born with multiple sclerosis and uses a wheelchair, almost became stuck on a train because staff at Egham station were not trained to operate a ramp to help her get off.
"I became panicked I wouldn't be able to get off the train," said the athlete.
"Luckily there were two guys who helped me get my wheelchair onto the platform, I couldn't thank them enough."
The part-time medical statistician, who grew up in Sunningdale but moved to Boyn Hill Avenue in Maidenhead in January, has to have an able-bodied person travelling with her whenever she uses public transport through fear she may get stuck.
Despite competing in two Paralympic games and being awarded an MBE, she said the situation has robbed her of 'spontaneity' and 'independence'.
She has to book assisted travel 24-hours in advance and struggles travelling through London as very few underground stations have wheelchair access.
Sophie, who is a patron for SportsAble based in Braywick Road, said generally people are helpful towards disabled travellers but more needs to be done to ensure they are treated fairly.
"I've never had any problems at Maidenhead train station but the same cannot be said for stations in London," she said.
"With the Paralympic games just around the corner, I thought the Government may have been motivated to do something to address the problem of accessibility, but I guess they don't think the same as me."
She will be competing for a place in the equestrian team GB in July for this year's Paralympics.
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