could you briefly explain what does write to live and work in UK without sponsorship means

When applying for roles based in the United Kingdom, applicants are required to have the right to live and work in the United Kingdom. This allows for them to ensure the correct taxes are paid and that the employee has the ability to carry out their role without restriction. To meet the criteria this would mean that you either already live/reside in the UK as a British Citizen or are living the the United Kingdom already on a visa which allows you to work without any restrictions. In some instances an employer may be able to act as a sponsor support the colleague in obtaining their visa so they can work in the United Kingdom however this is not offered currently with roles at British Airways. I hope that helps!