A 92-year-old woman who was almost deported to South Africa has handed in a petition at No 10 calling for a change in government policy.
More than 150,000 people signed their support for Myrtle Cothill when she was ordered to fly home by the Home Office.
The government eventually relented due to "compassionate and exceptional circumstances".
Mrs Cothill has been cared for by her daughter Mary Willis in Poole since coming to the UK in 2014.
She hopes the government will rethink its visa policy around adult dependency, and give leniency to those who cannot afford long term care in their native country.
The widow, who came to the UK on a tourist visa, has heart problems, is losing her eyesight and cannot walk unaided.
She sold her house in South Africa so she could live with her daughter, but did not apply for UK residency.
Mrs Cothill had been ordered to take a flight back to Johannesburg after her case was heard by immigration tribunals, but the Home Office halted proceedings.
Along with the petition, Mrs Cothill handed over a letter from her lawyer to Home Secretary Theresa May, which said there were "wider human rights implications for British citizens... wishing to look after vulnerable relatives".
He added that laws failed to protect the public's "deep held conviction in the importance of the family and the wish to look after vulnerable relatives in their hour of need".
The Home Office said applicants should apply from overseas first, and that it had reformed its rules in 2012 following a consultation.
It added: "This was because of the significant NHS and social care costs... the route now provides for those most in need of care, but not for those who simply prefer to come to live in the UK."