The kit contains a long cotton-wool bud, used to swab the lining of the vagina for about 20 seconds.
This is sent to a laboratory to test for human papillomavirus (HPV) which causes most cervical cancers.
If this is positive, they are invited for a further test to see if any cells in the cervix have started the journey to becoming a cancer.
The trial ran in five London boroughs, in 2021, and 27,000 test kits were offered.
The results, published in eClinicalMedicine, showed:
If these results were replicated across the whole of England, the researchers estimate it would increase the proportion screened from 69.9% to 77.3% – about one million extra women over a three-year screening cycle.
The trial also showed self-testing reached women irrespective of their ethnicity or wealth.
