About 31,000 women will be offered the swab checks, which can help spot early signs of cervical cancer.
About 31,000 women in London are being offered “do-it-at-home” tests to check for early warnings of cervical cancer, as part of an NHS trial.
It could be a way to encourage more women to get screened, experts hope.
Embarrassment, cultural barriers and worries about Covid, along with many other factors, can stop women going for smear tests at a clinic or GP surgery.
Smear-test delays during the pandemic prompted calls for home-screening kits from cervical cancer charities.
The swabbing involves using a long, thin cotton bud to take a sample from inside the vagina, which is then sent by post for testing.
Self-sampling is already offered in countries such as Denmark and Australia.
Women aged 25-64, overdue for a check and living in Barnet, Camden, Islington, Newham or Tower Hamlets will be offered a kit from their GP or in the post.
If the results reveal an infection called human papillomavirus (HPV) they will be invited to their GP for a standard smear test to closely examine the cells of their cervix.
HPV infections can cause these to change, sometimes developing into cancer.
Finding and treating cancer early can save lives.
Cancer Research UK said it was not yet known how effective and accurate self-sampling could be in cervical screening.
In-person screenings in Scotland, Wales and Northern Ireland have restarted after being halted during the first coronavirus lockdown.
In England, the NHS told GPs and clinics not to halt smear tests – but some patients have experienced cancellations and long waiting times.
About 600,000 tests failed to go ahead in the UK last April and May, Jo’s Cervical Cancer Trust said, in addition to a backlog of 1.5 million appointments missed annually.
Dr Anita Lim, from King’s College London, who is leading the YouScreen trial, said: “Women who don’t come for regular screening are at the highest risk of developing cervical cancer.
“So it is crucial that we find ways like this to make screening easier and protect women from what is a largely preventable cancer.
“Self-sampling is a game-changer.
“This simple and convenient swab means it can be done in the privacy and comfort of your own home.”
National clinical director for cancer for the NHS in England Prof Peter Johnson said: “GPs have taken extra precautions to make surgeries safe.
“And these home kits give thousands of women another option to keep up to date with their screening.”